View source for Acronym

{{Short description|Abbreviation consisting of initial letters of a phrase}}
{{About|linguistic abbreviation|the HTML element|ACRONYM tag|the political advocacy group|Acronym (organization)}}
{{Use mdy dates|date=August 2025}}
[[File:NASA_logo.svg|thumb|The name of [[NASA]] is an acronym that expands to National Aeronautics and Space Administration.]]

An '''acronym''' is an abbreviation formed using the initial letters of a multi-word name or phrase. Acronyms are often spelled with the initial letter of each word in [[all caps]] with no punctuation.

{{Anchor|initialism}}
In English the word is used in two ways. In the narrow sense, an acronym is a sequence of letters (representing the initial letters of words in a phrase) when pronounced together as a single word; for example, ''[[NASA]]'', ''[[NATO]]'', or ''[[laser]]''. In the broad sense, the term includes this kind of sequence when pronounced letter by letter (such as ''[[GDP]]'' or ''[[USA]]''). Sources that differentiate the two often call the former acronyms and the latter '''initialisms'''<ref>{{cite web |url=https://languagehumanities.org/what-is-the-difference-between-an-acronym-alphabetism-and-initialism.htm |title=What is the Difference Between an Acronym, Alphabetism, and Initialism? |last=McMahon|first=Mary |date=December 30, 2023 |publisher=LanguageHumanities.org |access-date=February 9, 2024}}</ref><ref>{{cite web |url=https://proofed.com/writing-tips/acronyms-vs-initialisms-whats-the-difference |title=Acronyms vs. Initialisms: What's the Difference? |date=April 3, 2022 |publisher=Proofed.com |access-date=January 24, 2024}}</ref><ref name="Brinton_Page_110">{{cite book |last1=Brinton|first1=Laurel J. |last2=Brinton|first2=Donna M. |title=The Linguistic Structure of Modern English |date=2010 |publisher=[[John Benjamins Publishing Company]] |location=Amsterdam |isbn=978-90-272-8824-0 |page=110 |url= https://books.google.com/books?id=1EeND5SyUuwC&pg=PA110 |access-date=April 3, 2022}}</ref> or '''alphabetisms'''. However, ''acronym'' is popularly used to refer to either concept,<ref name="Merriam-Webster_note">{{cite Merriam-Webster|acronym |access-date=January 22, 2020}} {{Cite web |url=https://www.merriam-webster.com/dictionary/acronym |title=Archived copy |access-date=June 8, 2020 |archive-date=January 22, 2020 |archive-url=https://archive.today/20200122212129/https://www.merriam-webster.com/dictionary/acronym |url-status=bot: unknown }}. "Some people feel strongly that ''acronym'' should only be used for terms like ''[[NATO]]'', which is pronounced as a single word, and that ''initialism'' should be used if the individual letters are all pronounced distinctly, as with ''[[Federal Bureau of Investigation|FBI]]''. Our research shows that ''acronym'' is commonly used to refer to both types of abbreviations."</ref> and both senses of the term are attributed as far back as the 1940s.<ref>{{cite journal | last1 = Zimmer | first1 = Ben | last2 = Carson | first2 = Charles E. | last3 = Solomon | first3 = Jane | title = Seventy-Five Years among the New Words | journal = American Speech | volume = 91 | issue = 4 | pages = 472–512 | date = 2016 | doi = 10.1215/00031283-3870163 | url = https://www.academia.edu/89372423}}</ref> Dictionary and style-guide editors dispute whether the term ''acronym'' can be legitimately applied to abbreviations which are not pronounced as words, and there is no general agreement on standard acronym [[space (punctuation)|spacing]], [[letter case|casing]], and punctuation.

{{Anchor|Expansion}}
The phrase that the acronym stands for is called its {{em|expansion}}. The {{em|meaning}} of an acronym includes both its expansion and the meaning of its expansion.

== Etymology ==
The word ''acronym'' is formed from the [[Greek root]]s {{lang|grc-Latn|akro-}}, meaning 'height, summit, or tip', and {{lang|grc-Latn|-nym}}, 'name'.<ref>{{cite encyclopedia | encyclopedia=[[Oxford English Dictionary]] third edition |title= acronym |url= https://www.oed.com/dictionary/acronym_n?tl=true&tab=factsheet |access-date=5 September 2025| date= |publisher=Oxford University Press}}</ref><ref>{{cite web |title=acronym |publisher=[[Merriam Webster Dictionary]] |url= https://www.merriam-webster.com/dictionary/acronym |accessdate= 5 September 2025}}</ref>  This [[neoclassical compound]] appears to have originated in German, with attestations for the German form {{lang|de|Akronym}} appearing as early as 1921.<ref name="Brockhaus_Handbuch">{{Cite encyclopedia |url= https://books.google.com/books?id=O9tFuwEACAAJ&pg=PA37 |via=Google Books |dictionary=Brockhaus Handbuch des Wissens in vier Bänden |title=Akronym |date=1921 |publisher=[[F. A. Brockhaus AG]] |location=Leipzig |language=de |volume=1 |page=37 |quote=Agfa (Aktien-Gesellschaft für Anilinfabrikation) |access-date=February 22, 2020}}</ref> Citations in English date to a 1940 translation of a novel by the German writer [[Lion Feuchtwanger]].<ref name="Paris_Gazette">{{Cite book |last=Feuchtwanger |first=Lion |author-link=Lion Feuchtwanger |title=Paris Gazette |publisher=Viking Press |date=1940 |isbn=1-135-37010-9 |location=New York |pages=665–66 |chapter=Chapter 47: Beasts of Prey |language=de |translator1-last=Muir |translator1-first=Willa |translator1-link=Willa Muir |translator-last2=Muir |translator-first2=Edwin |translator2-link=Edwin Muir |quote=His first glance at the ''Paris German News'' told Wiesener that this new paper was nothing like the old ''P.G.''. 'They can call it the ''P.G.N.'' if they like', he thought, 'but that's the only difference. Pee-gee-enn; what's the word for words like that, made out of initials? My memory is beginning to fail me. Just the other day there was a technical expression I couldn't remember. I must be growing old. ''P.G.'' or ''P.G.N.'', it's six of one and half a dozen of the other.&nbsp;... Pee-gee-enn. It's an acronym, that's what it is. That's what they call words made up of initials. So I remember it after all; that's at least something.}}</ref>

== Dispute over the scope of ''acronym'' ==
English [[lexicography]] and [[style guide]]s differ on whether ''acronym'' should apply only to abbreviations pronounced as ordinary words or also to letter-by-letter initialisms. Some authorities accept or record the broader sense; others restrict ''acronym'' to word-pronounced forms and prefer ''initialism'' (or simply ''abbreviation'') for the rest. Among sources that acknowledge the broader sense, attitudes range from neutral recording to prescriptive criticism.{{efn|Quotations from dictionary entries and usage notes are provided in the references for readers who need the exact wording.}}

=== Dictionaries ===
Some mainstream English dictionaries from across the English-speaking world affirm a sense of ''acronym'' that does not require its pronunciation as a word. American English dictionaries such as ''[[Merriam-Webster]]'',<ref name="Merriam-Webster">{{cite web |title=Acronym. |url= http://www.m-w.com/dictionary/acronym |website=The Merriam-Webster.com Dictionary |publisher=Merriam-Webster Inc. |access-date=January 22, 2020 |archive-url= https://archive.today/20200122212129/https://www.merriam-webster.com/dictionary/acronym |archive-date=January 22, 2020 |date=January 22, 2020}} {{blockquote|text='''acronym''' noun<br />ac·ro·nym {{!}} \ˈa-krə-ˌnim\ <br />Definition of ''acronym''<br />: a word (such as ''NATO'', ''radar'', or ''laser'') formed from the initial letter or letters of each of the successive parts or major parts of a compound term <br />''also'' : an abbreviation (such as ''FBI'') formed from initial letters : {{Smallcaps|initialism}}}}</ref> Dictionary.com's ''[[Random House Webster's Unabridged Dictionary]]''<ref name="Dictionary.com">{{cite web |title=Acronym. |url= https://www.dictionary.com/browse/acronym?s=t |website=Dictionary.com |access-date=January 22, 2020 |archive-url= https://archive.today/20200122212526/https://www.dictionary.com/browse/acronym?s=t |archive-date=January 22, 2020 |date=January 22, 2020 |quote=2. a set of initials representing a name, organization, or the like, with each letter pronounced separately; an initialism. |url-status=live}}</ref> and the ''[[American Heritage Dictionary]]''<ref name="AHD5">{{cite web |title=Acronym. |url= https://ahdictionary.com/word/search.html?q=acronym |website=The American Heritage Dictionary of the English Language |edition=Fifth |publisher=Houghton Mifflin Harcourt |access-date=January 22, 2020 |archive-url= https://archive.today/20200122220158/https://ahdictionary.com/word/search.html?q=acronym |archive-date=January 22, 2020 |date=November 2011 |url-status=live}}{{blockquote|ac·ro·nym (ăk'''′'''rə-nĭm′)<br /> ''n.''<br /> '''1.''' A word formed by combining the initial letters of a multipart name, such as ''NATO'' from ''N''orth ''A''tlantic ''T''reaty ''O''rganization or by combining the initial letters or parts of a series of words, such as ''radar'' from ''ra''dio ''d''etecting ''a''nd ''r''anging.<br /> '''2.''' ''Usage Problem'' An initialism.<br />[{{Smallcaps|acr(o)- + -onym.}}]<br />ac′ro·nym'''′'''ic, a·cron'''′'''y·mous (ə-krŏn′ə-məs) ''adj.''<br />'''''Usage Note:''''' In strict usage, the term ''acronym'' refers to a word made from the initial letters or parts of other words, such as ''sonar'' from ''so(und) na(vigation and) r(anging)''. The distinguishing feature of an acronym is that it is pronounced as if it were a single word, in the manner of ''NATO'' and ''NASA''. Acronyms are often distinguished from initialisms like ''FBI'' and ''NIH'', whose individual letters are pronounced as separate syllables. While observing this distinction has some virtue in precision, it may be lost on many people, for whom the term ''acronym'' refers to both kinds of abbreviations.}}</ref> as well as the British ''[[Oxford English Dictionary]]''<ref name="OED">{{cite web |website=Oxford English Dictionary |edition=Third |title=acronym, n. |url= https://www.oed.com/view/Entry/1844 |publisher=Oxford University Press |access-date=January 22, 2020 |date=December 2011 |archive-url= https://archive.today/20200122222116/https://www.oed.com/view/Entry/1844 |archive-date=January 22, 2020 |url-status=live}}
{{blockquote|'''acronym, ''n.'''''<br />
'''Pronunciation:''' Brit. /ˈakrənɪm/, U.S. /ˈækrəˌnɪm/<br />
'''Origin:''' Formed within English, by compounding; modelled on a German lexical item.<br />
'''Etymons:''' {{smallcaps|acro-}} comb. form, {{smallcaps|-onym}} comb. form.<br />
'''Etymology:''' < {{smallcaps|acro-}} comb. form + {{smallcaps|-onym}} comb. form, after German ''Akronym'' (1921 or earlier).<br />
Originally ''U.S.''<br />
'''1.''' A group of initial letters used as an abbreviation for a name or expression, each letter or part being pronounced separately; an initialism (such as ''ATM'', ''TLS'').<br />
In the ''O.E.D.'' the term ''initialism'' is used for this phenomenon. (See sense 2 for ''O.E.D.'' use of the word.)<br />
{{plainlist|indent=1}}
* {{hanging indent|text=1940 {{smallcaps|W. Muir & E. Muir}} tr. L. Feuchtwanger ''Paris Gaz.'' {{smallcaps|iii.}} xlvii. 518{{in5}}Pee-gee-enn. It's an acronym [Ger. ''Akronym''], that's what it is. That's what they call words made up of initials.}}
* {{hanging indent|text=1947 {{smallcaps|T. M. Pearce}} in ''Word Study'' May 8/2{{in5}}The acronym DDT..trips pleasantly on the tongue and is already a household byword.}}
* {{hanging indent|text=1959 ''Rotarian'' May 43/1{{in5}}DDD, an acronym that sounds more like a cattle brand.}}
* {{hanging indent|text=1975 ''Jet'' 24 July 9/1{{in5}}The puns on the acronym, 'CIA', were spawned by recent disclosures about the intelligence agency.}}
* {{hanging indent|text=1985 {{smallcaps|C. Jencks}} ''Mod. Movements in Archit.'' (ed. 2) i. 75{{in5}}Called by the acronym SCSD (Schools Construction System Development).}}
* {{hanging indent|text=2008 ''Atlantic Monthly'' June 104/2{{in5}}The acronym TSS—''Tout Sauf Sarkozy'' ('Anything But Sarkozy').}}
{{endplainlist}}
'''2.''' A word formed from the initial letters of other words or (occasionally) from the initial parts of syllables taken from other words, the whole being pronounced as a single word (such as ''NATO'', ''RADA'').<br />
{{plainlist|indent=1}}
* {{hanging indent|text=1943 ''Amer. Notes & Queries'' Feb. 167/1{{in5}}Words made up of the initial letters or syllables of other words..I have seen..called by the name ''acronym''.}}
* {{hanging indent|text=1947 ''Word Study'' 6(''title''){{in5}}Acronym Talk, or 'Tomorrow's English'.}}
* {{hanging indent|text=1950 {{smallcaps|S. Potter}} ''Our Lang.'' 163{{in5}}Acronyms or telescoped names like ''nabisco'' from ''National Biscuit Company''.}}
* {{hanging indent|text=1959 ''Times'' 1 Sep 22/3{{in5}}New words which are constructed out of initial letters are called, I understand, acronyms.}}
* {{hanging indent|text=1961 ''Electronics'' 21 Apr 51/2{{in5}}Colidar, an acronym from coherent light detecting and ranging.}}
* {{hanging indent|text=1976 {{smallcaps|P. R. Hutt}} in ''IBA Techn. Rev.'' {{smallcaps|ix.}} 4/2{{in5}}The author hit on the idea of the name 'oracle'..and it was not long before it was made into an acronym for 'Optional Reception of Announcements by Coded Line Electronics'.}}
* {{hanging indent|text=2009 ''N.Y. Times'' (National ed.) Apr 16 {{smallcaps|a}}2/2{{in5}}Turning tea into an acronym for Taxed Enough Already, demonstrators were expected to attend more than 750 rallies to protest government spending.}}{{endplainlist}}}}</ref> and the Australian ''[[Macquarie Dictionary]]''<ref name="Macquarie">{{cite web |title=acronym |url= https://www.macquariedictionary.com.au/features/word/search/acronym/ |website=Macquarie Dictionary |publisher=Macmillan Publishers Australia |access-date=January 22, 2020 |archive-url= https://archive.today/20200303014940/https://www.macquariedictionary.com.au/features/word/search/acronym/ |archive-date=March 3, 2020 |url-status=live}}{{blockquote|'''acronym'''<br />/ˈækrənɪm/ (''''say'''' 'akruhnim)<br />''noun'' '''1. ''' a word formed from the initial letters of a sequence of words, as ''radar'' (from ''radio detection and ranging'') or ''ANZAC'' (from ''Australian and New Zealand Army Corps''). Compare '''initialism'''.<br />'''2. ''' an initialism.<br />[{{smallcaps|acro-}} + ''-''(''o'')''nym''; modelled on {{smallcaps|synonym}}]}}</ref> all include a sense in their entries for ''acronym'' equating it with ''initialism'', although ''The American Heritage Dictionary'' criticizes it with the label "usage problem".<ref name="AHD5" /> However, many English language dictionaries, such as the ''[[Collins COBUILD Advanced Dictionary]]'',<ref name="Collins">{{cite web |title=acronym |url= https://www.collinsdictionary.com/dictionary/english/acronym |website=Collins COBUILD Advanced English Dictionary |publisher=HarperCollins Publishers |access-date=January 22, 2020 |quote=An acronym is a word composed of the first letters of the words in a phrase, especially when this is used as a name. An example of an acronym is 'NATO', which is made up of the first letters of the 'North Atlantic Treaty Organization'. |archive-url= https://web.archive.org/web/20200208100705/https://www.collinsdictionary.com/dictionary/english/acronym |archive-date=February 8, 2020 |url-status=live}}</ref> ''[[Cambridge Advanced Learner's Dictionary]]'',<ref name="Cambridge">{{cite web |title=acronym |url= https://dictionary.cambridge.org/dictionary/english/acronym |website=Cambridge Advanced Learner's Dictionary & Thesaurus |publisher=Cambridge University Press |access-date=January 22, 2020 |quote=an abbreviation consisting of the first letters of each word in the name of something, pronounced as a word |archive-url= https://web.archive.org/web/20200208100706/https://dictionary.cambridge.org/dictionary/english/acronym |archive-date=February 8, 2020 |url-status=live}}</ref> ''[[Macmillan Dictionary]]'',<ref name="Macmillan">{{cite web |title=acronym |url= https://www.macmillandictionary.com/dictionary/british/acronym |website=Macmillan Dictionary |publisher=Macmillan Education Limited |access-date=January 22, 2020 |quote=an abbreviation consisting of letters that form a word. For example, NATO is an acronym for the North Atlantic Treaty Organization. |archive-url= https://web.archive.org/web/20200405205208/https://www.macmillandictionary.com/dictionary/british/acronym |archive-date=April 5, 2020 |url-status=live}}</ref> ''[[Longman Dictionary of Contemporary English]]'',<ref name="Longman">{{cite web |title=acronym |url= https://www.ldoceonline.com/dictionary/acronym |website=Longman Dictionary of Contemporary English |publisher=Pearson Longman |access-date=January 22, 2020 |quote=a word made up from the first letters of the name of something such as an organization. For example, NATO is an acronym for the North Atlantic Treaty Organization. |archive-url= https://web.archive.org/web/20200405215403/https://www.ldoceonline.com/dictionary/acronym |archive-date=April 5, 2020 |url-status=live}}</ref> ''[[New Oxford American Dictionary]]'',<ref name="NOAD">{{Cite book |url= https://archive.org/details/newoxfordamerica0000unse_l5h7/page/15/mode/2up |title=New Oxford American dictionary. |date=2010 |publisher=Oxford University Press |isbn=978-0-19-539288-3 |edition=3rd |location=Oxford |page=15 |oclc=614990378 |url-access=registration}}{{blockquote|text='''ac·ro·nym''' /ˈakrəˌnim/ ▸ '''n.''' an abbreviation formed from the initial letters of other words and pronounced as a word (e.g. ''ASCII'', ''NASA'').<br />—{{Smallcaps|origin}} 1940s: from Greek ''akron'' 'end, tip' + ''onoma'' 'name,' on the pattern of ''homonym''.}}</ref> ''[[Webster's New World Dictionary]]'',<ref name="Websters-New-World">{{cite web |title=acronym |url= https://www.yourdictionary.com/acronym |website=Webster's New World College Dictionary, Fifth Edition |publisher=Houghton Mifflin Harcourt Publishing Company |access-date=January 22, 2020 |date=2014 |quote=a word formed from the first (or first few) letters of a series of words, as radar, from ''ra''dio ''d''etecting ''a''nd ''r''anging |archive-url= https://web.archive.org/web/20200405210057/https://www.yourdictionary.com/acronym |archive-date=April 5, 2020 |url-status=live}}</ref> and ''[[Lexico]]'' from Oxford University Press<ref name="Lexico">{{cite web |title=acronym |url= https://www.lexico.com/en/definition/acronym |website=Lexico |publisher=Oxford University Press |access-date=January 22, 2020 |quote=An abbreviation formed from the initial letters of other words and pronounced as a word (e.g. ASCII, NASA). |archive-url= https://web.archive.org/web/20191222132554/https://www.lexico.com/en/definition/acronym |archive-date=December 22, 2019 }}</ref> do not acknowledge such a sense.

=== Style and usage guides ===
English language usage and style guides which have entries for ''acronym'' generally criticize the usage that refers to forms that are not pronounceable words. ''[[Fowler's Dictionary of Modern English Usage]]'' says that ''acronym'' "denotes abbreviations formed from initial letters of other words and pronounced as a single word, such as ''NATO'' (as distinct from ''B-B-C'')" but adds later "In everyday use, ''acronym'' is often applied to abbreviations that are technically initialisms, since they are pronounced as separate letters."<ref name="Fowler2015">{{cite book |last=Fowler |first=Henry Watson |author-link=H. W. Fowler |editor=Jeremy Butterfield |title=[[Fowler's Dictionary of Modern English Usage]] |edition=4th |date=June 1, 2015 |publisher=Oxford University Press |isbn=978-0-19-966135-0 |page=[https://books.google.com/books?id=AvmzBgAAQBAJ&pg=PA16 16] }}</ref> ''[[The Chicago Manual of Style]]'' acknowledges the complexity ("Furthermore, an acronym and initialism are occasionally combined (JPEG), and the line between initialism and acronym is not always clear") but still defines the terms as mutually exclusive.<ref name="CMOS16">{{cite book|title=The Chicago Manual of Style|publisher=University of Chicago Press|isbn=978-0-226-10420-1|edition=16th|chapter=10.2 Acronyms, initialisms, contractions|year=2010|chapter-url-access=registration|chapter-url= https://archive.org/details/chicagomanualofs16edunse_2010}}</ref> Other guides outright deny any legitimacy to the usage: ''[[Bryson's Dictionary of Troublesome Words]]'' says "Abbreviations that are not pronounced as words (IBM, ABC, NFL) are not acronyms; they are just abbreviations."<ref name="Bryson2002">{{cite book |last=Bryson |first=Bill |author-link=Bill Bryson |title=Bryson's Dictionary of Troublesome Words |url= https://books.google.com/books?id=nwSm4UVY8uMC&pg=PT9 |date=September 17, 2002 |publisher=Crown |isbn=978-0-7679-1047-7 |page=9 |access-date=March 11, 2020}}</ref> ''[[Garner's Modern American Usage]]'' says "An acronym is made from the first letters or parts of a compound term. It's read or spoken as a single word, not letter by letter."<ref name="Garner2009">{{cite book |last=Garner |first=Bryan |author-link=Bryan Garner |title=[[Garner's Modern American Usage]] |date=July 28, 2009 |publisher=[[Oxford University Press]] |isbn=978-0-19-987462-0 |page=[https://books.google.com/books?id=Sd3byNeBdR4C&pg=PA2 2] }}</ref> ''[[The New York Times Manual of Style and Usage]]'' says "Unless pronounced as a word, an abbreviation is not an acronym."<ref name="SiegalConnolly2015">{{cite book |last1=Siegal |first1=Allan M. |author-link1=Allan M. Siegal |last2=Connoly |first2=William G. |author-link2=William G. Connolly |title=[[The New York Times Manual of Style and Usage]]: The Official Style Guide Used by the Writers and Editors of the World's Most Authoritative News Organization |edition=5th |date=2015 |publisher=Three Rivers Press |isbn=978-1-101-90544-9 |page=[https://books.google.com/books?id=AfbaCwAAQBAJ&pg=PA5 5] }}</ref>

In contrast, some style guides do support it, whether explicitly or implicitly. The 1994 edition of ''[[Merriam-Webster's Dictionary of English Usage]]'' defends the usage on the basis of a claim that dictionaries do not make a distinction.<ref name="MWDEU" /> The [[BuzzFeed]] style guide describes CBS and PBS as "acronyms ending in S".<ref name="BuzzFeed">{{cite web |first=Emmy |last=Favilla |date=December 27, 2019 |title=BuzzFeed Style Guide |url= https://www.buzzfeed.com/emmyf/buzzfeed-style-guide#2370665 |url-status=live |archive-url= https://web.archive.org/web/20200405210420/https://www.buzzfeed.com/emmyf/buzzfeed-style-guide#2370665 |archive-date=April 5, 2020 |access-date=January 22, 2020 |website=BuzzFeed.com |publisher=BuzzFeed}}</ref>

=== Historical development and antedating ===
Most of the dictionary entries and style guide recommendations regarding the term ''acronym'' in the twentieth century did not explicitly acknowledge or support the expansive sense. The [[Merriam–Webster's Dictionary of English Usage]] from 1994 is one of the earliest publications to advocate for the expansive sense,<ref name="MWDEU">Merriam-Webster, Inc. ''Merriam-Webster's Dictionary of English Usage'', 1994. {{ISBN|0-87779-132-5}}. pp. 21–22:
{{blockquote|'''acronyms'''&nbsp;&nbsp;A number of commentators (as Copperud 1970, Janis 1984, Howard 1984) believe that acronyms can be differentiated from other abbreviations in being pronounceable as words. Dictionaries, however, do not make this distinction because writers in general do not:
{{blockquote|"The powder metallurgy industry has officially adopted the acronym 'P/M Parts{{'"}}—''Precision Metal Molding'', January 1966.<br />"Users of the term ''acronym'' make no distinction between those pronounced as words ... and those pronounced as a series of characters" —Jean Praninskas, ''Trade Name Creation'', 1968.<br />"It is not J.C.B.'s fault that its name, let alone its acronym, is not a household word among European scholars"—''Times Literary Supp.'' February 5, 1970.<br />"...&nbsp;the confusion in the Pentagon about abbreviations and acronyms—words formed from the first letters of other words"—Bernard Weinraub, ''N.Y. Times'', December 11, 1978.}}Pyles & Algeo 1970 divide acronyms into "initialisms", which consists of initial letters pronounced with the letter names, and "word acronyms", which are pronounced as words. ''Initialism'', an older word than ''acronym'', seems to be too little known to the general public to serve as the customary term standing in contrast with ''acronym'' in a narrow sense.}}</ref> and all the major dictionary editions that include a sense of ''acronym'' equating it with ''initialism'' were first published in the twenty-first century. The trend among dictionary editors appears to be towards including a sense defining ''acronym'' as ''initialism'': the ''[[Merriam-Webster's Collegiate Dictionary]]'' added such a sense in its 11th edition in 2003,<ref name="MW10">{{Cite book |title=[[Merriam-Webster's Collegiate Dictionary]] |date=1993 |publisher=[[Merriam-Webster]] |isbn=0-87779-708-0 |edition=10th |location=Springfield, Massachusetts |oclc=27432416 |page=11 |quote='''ac·ro·nym''' ˈa-krə-ˌnim ''n'' [''acr-'' + ''-onym''] (1943) : a word (as ''NATO'', ''radar'', or ''snafu'') formed from the initial letter or letters of each of the successive parts or major parts of a compound term— '''ac·ro·nym·ic''' ˌa-krə-ˈni-mik ''adj'' — '''ac·ro·nym·i·c·al·ly''' -mi-k(ə-)lē ''adv''}}</ref><ref name="MW11">{{Cite book |title=[[Merriam-Webster's Collegiate Dictionary]] |date=2003 |publisher=[[Merriam-Webster]] |isbn=0-87779-809-5 |edition=11th |location=Springfield, Massachusetts |oclc=51764057 |page=[https://archive.org/details/merriamwebsters00spri/page/12 12] |via=Internet Archive |quote='''ac·ro·nym''' ˈa-krə-ˌnim ''n'' [''acr-'' + ''-onym''] (1943) : a word (such as ''NATO'', ''radar'', or ''laser'') formed from the initial letter or letters of each of the successive parts or major parts of a compound term; ''also'' : an abbreviation (such as ''FBI'') formed from initial letters : {{Smallcaps|initialism}}— '''ac·ro·nym·ic''' ˌa-krə-ˈni-mik ''adj'' — '''ac·ro·nym·i·c·al·ly''' -mi-k(ə-)lē ''adv''}}</ref> and both the ''[[Oxford English Dictionary]]''<ref name="OED1989">{{Cite web |url= https://www.oed.com/oed2/00002102 |access-date=January 28, 2020 |title=acronym |website=[[Oxford English Dictionary]] |edition=3rd |date=1989 |quote=A word formed from the initial letters of other words. |archive-url= https://web.archive.org/web/20190325224324/http://www.oed.com/oed2/00002102 |archive-date=March 25, 2019 |url-status=live}}</ref><ref name="OED" /> and ''[[The American Heritage Dictionary]]''<ref name="AHD4">{{Cite book |title=[[The American Heritage Dictionary of the English Language]] |date=2000 |publisher=Houghton Mifflin |isbn=0-395-82517-2 |edition=4th |location=Boston |oclc=43499541 |article=acronym |page=16 |quote=ac·ro·nym (ăk'''′'''rə-nĭm′) ''n.'' A word formed from the initial letters of a name, such as ''WAC'' for ''W''omen's ''A''rmy ''C''orps, or by combining initial letters or parts of a series of words, such as ''radar'' for ''ra''dio ''d''etecting ''a''nd ''r''anging. [{{Smallcaps|acr(o)- + -onym.}}]—ac′ro·nym'''′'''ic, a·cron'''′'''y·mous (ə-krŏn′ə-məs) ''adj.''}}</ref><ref name=AHD5 /> added such senses in their 2011 editions. The 1989 edition of the ''Oxford English Dictionary'' only included the exclusive sense for ''acronym'' and its earliest citation was from 1943.<ref name="OED1989" /> In early December 2010, [[Duke University]] researcher Stephen Goranson published a citation for ''acronym'' to the [[American Dialect Society]] e-mail discussion list which refers to ''PGN'' being pronounced "pee-gee-enn", [[antedating (lexicography)|antedating]] English language usage of the word to 1940.<ref>{{Cite web|url= https://listserv.linguistlist.org/pipermail/ads-l/2010-December/105190.html|title=acronym antedated to 1940|last=Goranson|first=Stephen|date=December 5, 2010|website=American Dialect Society E-Mail Discussion List Archive|url-status=live|archive-url= https://web.archive.org/web/20200405220548/http://listserv.linguistlist.org/pipermail/ads-l/2010-December/105190.html|archive-date=April 5, 2020|access-date=March 5, 2020}}</ref> Linguist [[Ben Zimmer]] then mentioned this citation in his December 16, 2010 "[[On Language]]" column about acronyms in ''[[The New York Times Magazine]]''.<ref>{{Cite news |last=Zimmer |first=Ben |url= https://www.nytimes.com/2010/12/19/magazine/19FOB-onlanguage-t.html |title=On Language: Acronym |date=December 16, 2010 |work=[[The New York Times Magazine]] |access-date=March 4, 2020 |url-status=live|archive-url= https://web.archive.org/web/20200405220123/https://www.nytimes.com/2010/12/19/magazine/19FOB-onlanguage-t.html|archive-date=April 5, 2020}}</ref> By 2011, the publication of the 3rd edition of the ''Oxford English Dictionary'' added the expansive sense to its entry for ''acronym'' and included the 1940 citation.<ref name="OED" /> As the ''Oxford English Dictionary'' structures the senses in order of chronological development,<ref>{{Cite web |url= https://public.oed.com/how-to-use-the-oed/glossary/#sense |title=OED terminology |website=[[Oxford English Dictionary]] |edition=3rd |archive-url= https://web.archive.org/web/20200327185842/https://public.oed.com/how-to-use-the-oed/glossary/#sense|archive-date=March 27, 2020 |access-date=January 28, 2020}}</ref> it now gives the "initialism" sense first.

==Examples==
{{main|Lists of acronyms}}
<!--
LIMIT TO FOUR EXAMPLES OF EACH TYPE. 
There are lists of acronyms elsewhere.
And no cheating by adding silly categories :)
-->
*Pronounced as letters
**[[British Broadcasting Corporation|BBC]]: "British Broadcasting Corporation"
**DVD: "Digital Video Disc"
**[[OEM]]: "original equipment manufacturer"
**[[VHF]]: "very high frequency"
*Pronounced as word; initials only
**[[NATO]]: "North Atlantic Treaty Organization"
**[[Scuba set|Scuba]]: "self-contained underwater breathing apparatus"
**[[Laser]]: "light amplification by stimulated emission of radiation"
**[[GIF]]: "graphics interchange format"
*Pronounced as word; initials and non-initials
**[[Amphetamine]]: "alpha-methyl-phenethylamine"
**{{lang|de|[[Gestapo]]}}: German {{lang|de|Geheime Staatspolizei}} ('secret state police')
**[[Radar]]: "radio detection and ranging"
**[[Lidar]]: "light detection and ranging"
*Pronounced as combination of word and letters
**[[CD-ROM]]: (''cee-dee-''{{IPAc-en|r|ɒ|m|}}) "compact disc read-only memory"
**[[IUPAC]]: (''i-u-''{{IPAc-en|p|æ|k|}} or ''i-u-pee-a-cee'') "International Union of Pure and Applied Chemistry"
**[[JPEG]]: (''jay-''{{IPAc-en|p|ɛ|ɡ}} or ''jay-pee-e-gee'') "Joint Photographic Experts Group"
**[[San Francisco Museum of Modern Art|SFMOMA]]: (''ess-ef-''{{IPAc-en|ˈ|m|oʊ|m|ə}} or ''ess-ef-em-o-em-a'') "San Francisco Museum of Modern Art"
*Pronounced as shortcut phrase of letters
**AAA:
***(''Triple-A'') "[[American Automobile Association]]"; "[[abdominal aortic aneurysm]]"; "[[anti-aircraft artillery]]"; "[[Asistencia, Asesoría y Administración]]"
***(''Three-As'') "[[Amateur Athletic Association]]"
**[[Institute of Electrical and Electronics Engineers|IEEE]]: (''I triple-E'') "Institute of Electrical and Electronics Engineers"
**[[National Association for the Advancement of Colored People|NAACP]]: (''N double-A C P'' or ''N A A C P'') "National Association for the Advancement of Colored People"
**[[National Collegiate Athletic Association|NCAA]]: (''N C double-A'' or ''N C two-A'' or ''N C A A'') "National Collegiate Athletic Association"
*Shortcut incorporated into spelling
**[[3M]]: (''three M'') originally "Minnesota Mining and Manufacturing Company"
**[[W3C]]: (''W-three C'') "World Wide Web Consortium"
**[[A2DP]]: (''A-two D P'') "Advanced Audio Distribution Profile"
**[[I18N]]: (''"18" stands in for the word's middle eighteen letters, "nternationalizatio"'') "Internationalization"
**[[C4ISTAR]]: (''C-four Istar'') "Command, Control, Communications, Computers, Intelligence, Surveillance, Target Acquisition, and Reconnaissance"<ref>{{Cite book|last=Robinson |first=Paul |title=Dictionary of international security |publisher=Polity |year=2008 |page=31 |chapter=C4ISR |isbn=978-0-7456-4028-0 |chapter-url= https://books.google.com/books?id=oy9GzLqkMr0C&pg=PA31}}</ref>
*Mnemonic (memory-aid)
**[[KISS principle|KISS]] "Keep it simple, stupid", a design principle preferring simplicity 
**[[SMART criteria|SMART]] "Specific, Measurable, Assignable, Realistic, Time-related", A principle of setting of goals and objectives
**[[FAST (stroke)|FAST]] "Facial drooping, Arm weakness, Speech difficulties, Time", helps detect and enhance responsiveness to the needs of a person having a stroke
**[[Don't repeat yourself|DRY]] "Don't repeat yourself", A principle of software development aimed at reducing repetition of software patterns
*Multi-layered
**[[AIM (software)|AIM]]: "AOL Instant Messenger", in which "[[AOL]]" originally stood for "America Online"
**[[ASEAN Free Trade Area|AFTA]]: "ASEAN Free Trade Area", where [[ASEAN]] stands for "Association of Southeast Asian Nations"
**[[GIMP]]: "[[GNU]] image manipulation program"
*[[Recursive acronyms|Recursive]]
**[[GNU]]: "GNU's not Unix!"<!-- Don't remove the apostrophe. It's a contraction for "GNU is", rather than the pluralization of "GNU"-->
**[[Wine (software)|Wine]]: "Wine is not an emulator" (originally, "Windows emulator")
**[[GNU Hurd|HURD]]: "HIRD of Unix-replacing daemons", where "HIRD" stands for "HURD of interfaces representing depth"
*[[Gramogram]]s, pseudo-acronyms<ref>{{cite web |url= http://www.hsdl.org/?view&did=6791 |title=Acronyms (and other forms of abbreviation) |publisher=[[US Department of Homeland Security]] |date=November 12, 2008 |access-date=June 10, 2014 |archive-url= https://web.archive.org/web/20140714170336/http://www.hsdl.org/?view&did=6791 |archive-date=July 14, 2014 |url-status=live}}</ref>
**[[CQ (call)|CQ]]: ''cee-cue'' for "seek you", a code used by radio operators
**[[IOU (debt)|IOU]]: ''i-o-u'' for "I owe you"
**[[Police dog|K9]]: ''kay-nine'' for "canine", used to designate police units using dogs
*[[RAS syndrome]] phrases
**[[Automated teller machine|ATM]] machine: "automated teller machine machine"
**[[Human immunodeficiency virus|HIV]] virus: "human immunodeficiency virus virus"
**[[Liquid-crystal display|LCD]] display: "liquid-crystal display display"
**[[Personal identification number|PIN]] number: "personal identification number number"
**[[Common Access Card|CAC]] card: "common access card card"

==Historical and current use==
{{more citations needed section|date=January 2015}}
Acronymy, like [[retronym]]y, is a linguistic process that has existed throughout history but for which there was little to no [[metalanguage|naming]], conscious attention, or [[linguistics|systematic analysis]] until relatively recent times. Like retronymy, it became much more common in the twentieth century than it had formerly been.

Ancient examples of acronymy (before the term "acronym" was invented) include the following:
* Acronyms were used in Rome before the Christian era. For example, the official name for the Roman Empire, and the Republic before it, was abbreviated as ''[[SPQR]]'' ({{lang|la|Senatus Populusque Romanus}}). Inscriptions dating from antiquity, both on stone and on coins, use many abbreviations and acronyms to save space and work. For example, [[Praenomen|Roman first names]], of which there was only a small set, were almost always abbreviated. Common terms were abbreviated too, such as writing just "F" for {{lang|la|filius}}, meaning "son", a very common part of memorial inscriptions mentioning people. Grammatical markers were abbreviated or left out entirely if they could be inferred from the rest of the text.
* So-called {{lang|la|[[nomina sacra]]}} ('sacred names') were used in many Greek biblical manuscripts. The common words God ({{lang|grc|Θεός}}), Jesus ({{lang|grc|Ιησούς}}), Christ ({{lang|grc|Χριστός}}), and some others, would be abbreviated by their first and last letters, marked with an overline. This was just one of many kinds of conventional scribal abbreviation, used to reduce the time-consuming workload of the scribe and save on valuable writing materials. The same convention is still commonly used in the inscriptions on religious [[icon]]s and the stamps used to mark the eucharistic bread in [[Eastern Christianity|Eastern Churches]].
* The early Christians in Rome, most of whom were Greek rather than Latin speakers, used the image of a fish as a symbol for Jesus in part because of an acronym (or [[backronym]]): 'fish' in Greek is {{transliteration|grc|[[ichthys]]}} ({{lang|grc|ΙΧΘΥΣ}}), which was construed to stand for {{lang|grc|{{lang|grc|Ἰησοῦς Χριστός Θεοῦ Υἱός Σωτήρ}}}} ({{transliteration|grc|Iesous Christos Theou huios Soter}}: 'Jesus Christ, God's Son, Savior'). This interpretation dates from the second and third centuries and is preserved in the [[catacombs]] of Rome. Another ancient acronym for Jesus is the inscription ''[[INRI]]'' over the crucifix, for the Latin {{lang|la|Iesus Nazarenus Rex Iudaeorum}} ('Jesus the Nazarene, King of the Jews').
* [[Hebrew language|Hebrew]] has a millennia-long history of acronyms pronounced as words. Along with theophoric parallels to the Greek described above, [[Talmud]]ic sages as early as [[Rabbi Yehuda]] shorten the [[ten plagues]] to דצ"ך עד"ש באח"ב, the order of blessings to יקנה"ז, etc., for the sake of [[mnemonic]]. The [[Rishonim|rishonic]] period saw Hebrew acronymy expand to a lexicon of many hundreds, including every type of word and extending to proper nouns: almost all Medieval rabbis are known by acronyms like ''[[Rashi]]'' and ''[[Maimonides|Rambam]].''

During the mid- to late nineteenth century, acronyms became a trend among American and European businessmen: abbreviating corporation names, such as on the sides of [[railroad car]]s (e.g., "Richmond, Fredericksburg and Potomac Railroad" → "RF&P"); on the sides of barrels and crates and newspaper stock listings (e.g. American Telephone and Telegraph Company → AT&T). Some well-known commercial examples dating from the 1890s through 1920s include "[[Nabisco]]" ("National Biscuit Company"),<ref name="Davenport">{{cite journal |first=Basil |last=Davenport |title=Initials into Words |journal=[[American Notes and Queries]] |url= https://archive.org/details/in.ernet.dli.2015.157029 |via=Internet Archive |date=February 1943 |volume=2 |page=167 |quote=Your correspondent who asks about words made up of the initial letters or syllables of other words may be interested in knowing that I have seen such words called by the name ''acronym'', which is useful and clear to anyone who knows a little Greek.}}</ref> "[[Esso]]" (from "S.O.", from "[[Standard Oil]]"), and "[[Sunoco]]" ("Sun Oil Company").

Another field for the adoption of acronyms was modern warfare, with its many highly technical terms. While there is no recorded use of military acronyms dating from the [[American Civil War]] (acronyms such as "ANV" for "[[Army of Northern Virginia]]" post-date the war itself), they became somewhat common in [[World War I]], and by [[World War II]] they were widespread even in the slang of soldiers,<ref name="etymonline.com2">{{cite web |url= http://www.etymonline.com/baloney.php |title=Baloney |website=Online Etymology Dictionary |first=Douglas |last=Harper |access-date=August 31, 2009 |archive-url= https://web.archive.org/web/20220417143143/http://www.snopes.com/language/acronyms/fuck.asp |archive-date=April 17, 2022 |url-status=live}}</ref> who referred to themselves as [[G.I. (military)|G.I.]]s.

The widespread, frequent use of acronyms across the whole range of linguistic [[register (sociolinguistics)|registers]] is relatively new in most languages, becoming increasingly evident since the mid-twentieth century. As literacy spread and technology produced a constant stream of new and complex terms, abbreviations became increasingly convenient. The ''[[Oxford English Dictionary]]'' (''OED'') records the first printed use of the word ''initialism'' as occurring in 1899, but it did not come into general use until 1965, well after ''acronym'' had become common.

In English, acronyms {{em|pronounced as words}} may be a twentieth-century phenomenon. Linguist David Wilton in ''Word Myths: Debunking Linguistic Urban Legends'' claims that "forming words from acronyms is a distinctly twentieth- (and now twenty-first-) century phenomenon. There is only one known pre-twentieth-century [English] word with an acronymic origin and it was in vogue for only a short time in 1886. The word is ''colinderies'' or ''colinda'', an acronym for the [[Colonial and Indian Exposition]] held in London in that year."<ref name="Wilton">{{cite book |url= https://archive.org/details/wordmythsdebunki00wilt_0 |url-access=registration |page=[https://archive.org/details/wordmythsdebunki00wilt_0/page/79 79] |quote=Word Myths: Debunking Linguistic Urban Legends. |title=Word myths: debunking linguistic urban legends |publisher=Oxford University Press, USA |last=Wilton |first=David |access-date=September 16, 2010 |isbn=978-0-19-517284-3 |date=2004}}</ref><ref>{{cite web |url=http://www.snopes.com/language/acronyms/acronyms.asp |archive-url=https://archive.today/20120910194026/http://www.snopes.com/language/acronyms/acronyms.asp |url-status=dead |archive-date=September 10, 2012 |title=Urban Legends Reference Pages: Language (Acronyms) |publisher=Snopes.com |access-date=September 16, 2010 }}</ref> However, although acronymic words seem not to have been {{em|employed in general vocabulary}} before the twentieth century (as Wilton points out), the {{em|concept of their formation}} is treated as effortlessly understood (and evidently not novel) in an [[Edgar Allan Poe]] story of the 1830s, "[[How to Write a Blackwood Article]]", which includes the contrived acronym "P.R.E.T.T.Y.B.L.U.E.B.A.T.C.H."

===Early examples in English===
The use of Latin and Neo-Latin terms in [[vernacular]]s has been pan-European and pre-dates modern English. Some examples of acronyms in this class are:

*''[[12-hour clock|A.M.]]'' (from Latin {{lang|la|ante meridiem}}, 'before noon') and ''[[12-hour clock|P.M.]]'' (from Latin {{lang|la|post meridiem}}, 'after noon')
*''A.D.'' (from Latin {{lang|la|[[Anno Domini]]}}, 'in the year of our Lord'), whose complement in English, ''B.C.'' ([[Before Christ]]), is English-sourced The earliest example of a word derived from an acronym listed by the ''[[Oxford English Dictionary|OED]]'' is "abjud" (now "[[abjad]]"), formed from the original first four letters of the [[Arabic alphabet]] in the late eighteenth century.<ref>{{citation |contribution=abjad, ''n.'' |contribution-url= http://www.oed.com/view/Entry/271930 |title=Oxford English Dictionary}}.</ref> Some [[acrostics]] pre-date this, however, such as the [[English Restoration|Restoration]] witticism arranging the names of some members of [[Charles II of England|Charles II]]'s Committee for Foreign Affairs to produce the [[Cabal ministry|"CABAL" ministry]].<ref>{{citation |contribution=cabal, ''n.'' |contribution-url= http://www.oed.com/view/Entry/25693 |title=Oxford English Dictionary}}.</ref>

''[[Okay|OK]]'', a term of disputed origin, dates back at least to the early nineteenth century and is now used around the world.

===Current use===
Acronyms are used most often to abbreviate names of organizations and long or frequently referenced terms. The [[Military|armed forces]] and government agencies frequently employ acronyms; some well-known examples from the United States are among the "[[alphabet agencies]]" (jokingly referred to as "[[Alphabet soup (linguistics)|alphabet soup]]") created under the [[New Deal]] by [[Franklin D. Roosevelt]] (himself known as "FDR"). Business and industry also coin acronyms prolifically. The rapid advance of science and technology also drives the usage, as new inventions and concepts with multiword names create a demand for shorter, more pronounceable names.{{citation needed|date=January 2015}} One representative example, from the U.S. Navy, is "COMCRUDESPAC", which stands for "commander, cruisers destroyers Pacific"; it is also seen as "ComCruDesPac". Inventors are encouraged to anticipate the formation of acronyms by making new terms "YABA-compatible" ("yet another bloody acronym"), meaning the term's acronym can be pronounced and is not an offensive word: "When choosing a new name, be sure it is 'YABA-compatible'."<ref>K. D. Nilsen & A. P. Nilsen (1995) ''The English Journal'' Vol. 84, No. 6., "Literary Metaphors and Other Linguistic Innovations in Computer Language"</ref>

Acronym use has been further popularized by text messaging on mobile phones with [[short message service]] (SMS), and [[instant messenger]] (IM). To fit messages into the 160-character SMS limit, and to save time, acronyms such as "GF" ("girlfriend"), "LOL" ("laughing out loud"), and "DL" ("download" or "down low") have become popular.<ref>{{cite book |last=Crystal |first=David |author-link=David Crystal |title=[[Txtng: The Gr8 Db8]] |publisher=[[Oxford University Press]] |date=2008 |isbn=978-0-19-954490-5}}</ref> Some [[Linguistic prescription|prescriptivist]]s disdain texting acronyms and abbreviations as decreasing clarity, or as failure to use "pure" or "proper" English. Others point out that languages have always [[language change|continually changed]], and argue that acronyms should be embraced as inevitable, or as innovation that adapts the language to changing circumstances. In this view, the modern practice is just the "proper" English of the current generation of speakers, much like the earlier abbreviation of corporation names on ticker tape or newspapers.

Exact pronunciation of "word acronyms" (those pronounced as words rather than sounded out as individual letters) often vary by speaker population. These may be regional, occupational, or generational differences, or simply personal preference. For instance, there have been decades of online debate about how to pronounce [[GIF]] ({{IPAc-en|g|ɪ|f}} or {{IPAc-en|dʒ|ɪ|f}}) and [[BIOS]] ({{IPAc-en|ˈ|b|aɪ|oʊ|s}}, {{IPAc-en|ˈ|b|aɪ|oʊ|z}}, or {{IPAc-en|ˈ|b|aɪ|ɒ|s}}). Similarly, some letter-by-letter initialisms may become word acronyms over time, especially in combining forms: ''IP'' for ''[[Internet Protocol]]'' is generally said as two letters, but ''[[IPsec]]'' for ''Internet Protocol Security'' is usually pronounced as {{IPAc-en|ˌ|aɪ|ˈ|p|i:|s|ɛ|k}} or {{IPAc-en|ˈ|ɪ|p|s|ɛ|k}}, along with variant capitalization like "IPSEC" and "Ipsec". Pronunciation may even vary within a single speaker's vocabulary, depending on narrow contexts. As an example, the database programming language [[SQL]] is usually said as three letters, but in reference to [[Microsoft SQL Server|Microsoft's implementation]] is traditionally pronounced like the word ''sequel''.

====Expansion at first use====
{{more citations needed section|date=January 2015}}
In writing for a broad audience, the words of an acronym are typically written out in full at its first occurrence within a given text. Expansion at First Use (EAFU) benefits readers unfamiliar with the acronym.<ref>{{cite web |last1=Lee |first1=Chelsea |title=An Abbreviations FAQ |url= https://blog.apastyle.org/apastyle/2015/10/an-abbreviations-faq.html#Q2 |access-date=June 3, 2020 |archive-url= https://web.archive.org/web/20200603074708/https://blog.apastyle.org/apastyle/2015/10/an-abbreviations-faq.html#Q2 |archive-date=June 3, 2020 |url-status=live}}</ref>

Another text aid is an abbreviation key which lists and expands all acronyms used, a reference for readers who skipped past the first use. (This is especially important for paper media, where no search utility is available to find the first use.) It also gives students a convenient review list to memorize the important acronyms introduced in a textbook chapter.

Expansion at first use and abbreviation keys originated in the print era, but they are equally useful for [[E-text|electronic text]].

====Jargon====
While acronyms provide convenience and succinctness for specialists, they often degenerate into confusing [[jargon]]. This may be intentional, to exclude readers without domain-specific knowledge. New acronyms may also confuse when they coincide with an already existing acronym having a different meaning.

Medical literature has been struggling to control the proliferation of acronyms, including efforts by the American Academy of Dermatology.<ref name="PMID19150279">{{Cite journal |last1=Patel |first1=C. B. |last2=Rashid |first2=R. M. |title=Averting the proliferation of acronymophilia in dermatology: effectively avoiding ADCOMSUBORDCOMPHIBSPAC |journal=Journal of the American Academy of Dermatology |volume=60 |issue=2 |pages=340–344 |date=February 2009 |pmid=19150279 |doi=10.1016/j.jaad.2008.10.035}}</ref>

====As mnemonics====
Acronyms are often taught as [[mnemonic]] devices: for example the colors of the rainbow are [[ROY G. BIV]] (red, orange, yellow, green, blue, indigo, violet). They are also used as mental checklists: in aviation [[GUMPS]] stands for gas-undercarriage-mixture-propeller-seat belts. Other mnemonic acronyms include HOMES (for the North American Great Lakes) in geography, PAVPANIC in English grammar, and [[PEMDAS]]/[[BODMAS]] in mathematics.

====Acronyms as legendary etymology====
{{See also|Backronym}}
It is not uncommon for acronyms to be cited in a kind of [[false etymology]], called a [[folk etymology]], for a word. Such etymologies persist in popular culture but have no factual basis in [[historical linguistics]], and are examples of language-related [[urban legend]]s. For example, "[[Police officer|cop]]" is commonly cited as being derived, it is presumed, from "constable on patrol",<ref>{{Cite web |url= http://www.snopes.com/language/acronyms/cop.asp |title=Does Cop = 'Constable on Patrol'? |date=May 3, 2007}}</ref> and "[[Posh (nautical term)|posh]]" from "[[port outward, starboard home]]".<ref name="posh">{{Cite book |title=Port Out, Starboard Home: And Other Language Myths |publisher=Penguin Books |last=Quinion |first=Michael |author-link=Michael Quinion |isbn=978-0-14-101223-0 |date=2005}}; published in the US as {{Cite book |title=Ballyhoo, Buckaroo, and Spuds |last=Quinion |first=Michael |date=2006 |publisher=HarperCollins |isbn=978-0-06-085153-8 |url-access=registration |url= https://archive.org/details/ballyhoobuckaroo0000quin_z4e2 |via=Internet Archive |access-date=March 4, 2020}}</ref> With some of these specious expansions, the "belief" that the etymology is acronymic has clearly been [[tongue-in-cheek]] among many citers, as with "gentlemen only, ladies forbidden" for "golf", although many other (more [[wikt:credulous|credulous]]) people have uncritically taken it for fact.<ref name="posh" /><ref>{{cite web |url= http://www.snopes.com/language/acronyms/golf.asp |title=See article at Snopes |date=February 20, 2002 |publisher=Snopes.com |access-date=September 16, 2010 |archive-url= https://web.archive.org/web/20220506042707/http://www.snopes.com/language/acronyms/golf.asp |archive-date=May 6, 2022 |url-status=live}}</ref> [[Taboo word]]s in particular commonly have such false etymologies: "[[shit]]" from "ship/store high in transit"<ref name="Wilton" /><ref name="etymonline.com2"/> or "special high-intensity training" and "[[fuck]]" from "for unlawful carnal knowledge", or "fornication under consent/command of the king".<ref name="etymonline.com2" />

==Orthographic styling==
===Punctuation===
====Showing the ellipsis of letters====
In English, abbreviations have previously been marked by a wide variety of [[English punctuation|punctuation]]. Obsolete forms include using an [[overbar]] or [[colon (punctuation)|colon]] to show the [[ellipsis]] of letters following the initial part. The [[forward slash]] is still common in many dialects for some fixed expressions{{mdash}}such as in ''w/'' for "with" or ''A/C'' for "[[air conditioning]]"{{mdash}}while only infrequently being used to abbreviate new terms. The [[apostrophe]] is common for [[Contraction (grammar)#English|grammatical contractions]] (e.g. ''don't'', ''[[y'all]]'', and ''[[ain't]]'') and for contractions marking unusual pronunciations (e.g. ''a'ight'', ''cap'n'', and ''fo'c'sle'' for "all right", "captain", and "forecastle"). By the early twentieth century, it was standard to use a [[full stop]]/period/point, especially in the cases of initialisms and acronyms. Previously, especially for [[Latin abbreviations]], this was done with a full space between every full word (e.g. {{lang|la|A. D.}}, {{lang|la|i. e.}}, and {{lang|la|e. g.}} for "[[Anno Domini]]", "[[id est]]", and "[[exempli gratia]]"). This even included punctuation after both [[Roman numerals|Roman]] and [[Arabic numerals]] to indicate their use in place of the full names of each number (e.g. ''LII.'' or ''52.'' in place of "fifty-two" and "1/4." or "1./4." to indicate "one-fourth"). Both conventions have fallen out of common use in all dialects of English, except in places where an Arabic [[decimal number|decimal]] includes a medial [[decimal point]].

Particularly in [[British English|British]] and [[Commonwealth English]], all such punctuation marking acronyms and other capitalized abbreviations is now uncommon and considered either unnecessary or incorrect. The presence of all-capital letters is now thought sufficient to indicate the nature of the ''UK'', the ''EU'', and the ''UN''. Forms such as ''the U.S.A.'' for "the United States of America" are now considered to indicate [[American English|American]] or [[North American English]]. Even within those dialects, such punctuation is becoming increasingly uncommon.<ref>[[Oxford English Dictionary]]: ''initialism''. "Globe & Mail (Toronto) 22 May 10/4 Americanization has also largely done away with periods in acronyms and initialisms."</ref>

=====Ellipsis-is-understood style=====
Some [[style guide]]s, such as that of the [[BBC]], no longer require punctuation to show [[ellipsis]]; some even proscribe it. [[Larry Trask]], American author of ''The [[Penguin Books|Penguin]] Guide to Punctuation'', states categorically that, in [[British English]], "this tiresome and unnecessary practice is now obsolete."<ref>{{cite web |url= http://www.informatics.susx.ac.uk/doc/punctuation/node28.html |title=Abbreviations |publisher=Informatics.Susx.ac.uk |access-date=September 16, 2010 |archive-url= https://web.archive.org/web/20070410113359/http://www.informatics.susx.ac.uk/doc/punctuation/node28.html |archive-date=April 10, 2007 }}</ref>

=====Pronunciation-dependent style and periods=====
Nevertheless, some influential [[style guide]]s, many of them [[American English|American]], still require periods in certain instances. For example, ''[[The New York Times Manual of Style and Usage]]'' recommends following each segment with a period when the letters are pronounced individually, as in "[[KGB|K.G.B.]]", but not when pronounced as a word, as in "[[NATO]]".<ref name = "NY Times">{{Cite news |url= https://www.nytimes.com/2004/02/07/opinion/secret-obsessions-at-the-top.html |access-date=October 10, 2015 |title=Secret Obsessions at the Top |first=Nicholas D. |last=Kristoff |work=[[The New York Times]] |date=February 7, 2004 |archive-url= https://web.archive.org/web/20150528024321/http://www.nytimes.com/2004/02/07/opinion/secret-obsessions-at-the-top.html |archive-date=May 28, 2015 |url-status=live}}</ref> The logic of this style is that the pronunciation is reflected graphically by the punctuation scheme.

=====Other conventions=====
When a multiple-letter abbreviation is formed from a single word, periods are in general not used, although they may be common in informal usage. "TV", for example, may stand for a ''single'' word ("television", for instance), and is in general spelled without punctuation (except in the plural). Although "PS" stands for the single English word "[[postscript]]" or the Latin ''postscriptum'', it is often spelled with periods ("P.S.") as if parsed as Latin ''post scriptum'' instead.

The [[slash (punctuation)|slash]] ('/', or ''solidus'') is sometimes used to separate the letters in an acronym, as in "N/A" ("not applicable, not available") and "c/o" ("care of").

Inconveniently long words used frequently in related contexts can be represented according to their letter count as a [[numeronym]]. For example, "i18n" abbreviates "[[internationalization]]", a computer-science term for adapting software for worldwide use; the "18" represents the 18 letters that come between the first and the last in "internationalization". Similarly, "localization" can be abbreviated "l10n"; "[[multilingualization]]" "m17n"; and "[[accessibility]]" "a11y". In addition to the use of a specific number replacing that many letters, the more general "x" can be used to replace an unspecified number of letters. Examples include "Crxn" for "crystallization" and the series familiar to physicians for [[medical history|history]], [[medical diagnosis|diagnosis]], and [[therapy|treatment]] ("hx", "dx", "tx"). Terms relating to a command structure may also sometimes use this formatting, for example gold, silver, and bronze levels of command in UK policing being referred to as Gx, Sx, and Bx.

====Representing plurals and possessives====
There is a question about how to pluralize acronyms. Often a writer will add an 's' following an apostrophe, as in "PC's". However, [[Kate L. Turabian]]'s ''[[A Manual for Writers of Research Papers, Theses, and Dissertations]]'', writing about style in academic writings,<ref name="Chicago">{{cite book |last1=Turabian |first1=Kate L. |author1-link=Kate L. Turabian |last2=Booth |first2=Wayne C. |last3=Colomb |first3=Gregory G. |last4=Williams |first4=Joseph M. |title=[[A Manual for Writers of Research Papers, Theses, and Dissertations]] |edition=7th |date=2007 |at=§&nbsp;20.1.2 |publisher=[[University of Chicago Press]] |isbn=978-0-226-82337-9}}</ref> allows for an apostrophe to form plural acronyms "only when an abbreviation contains internal periods or both capital and lowercase letters". Turabian would therefore prefer "DVDs" and "URLs" but not "Ph.D.s". The style guides of the [[Modern Language Association]]<ref name="MLA">{{cite book |publisher=[[Modern Language Association]] |title=[[MLA Handbook]] for Writers of Research Papers |edition=7th |date=2009 |at=§&nbsp;3.2.7.g}}</ref> and [[American Psychological Association]]<ref name="APA">{{cite book |title=Publication Manual of the American Psychological Association |edition=5th |date=2001 |at=§&nbsp;3.28 |publisher=[[American Psychological Association]]}}</ref><ref name=autogenerated1>{{cite book |title=[[Publication Manual of the American Psychological Association]] |edition=6th |date=2010 |at=§&nbsp;4.29 |publisher=[[American Psychological Association]]}}</ref> prohibit apostrophes from being used to pluralize acronyms regardless of periods (so "compact discs" would be "CDs" or "C.D.s"), whereas ''[[The New York Times Manual of Style and Usage]]'' requires an apostrophe when pluralizing all abbreviations regardless of periods (preferring "PC's, TV's and VCR's").<ref>{{cite book |last1=Siegal |first1=Allan M. |author1-link=Allan M. Siegal |last2=Connolly |first2=William G. |author2-link=William G. Connolly |title=[[The New York Times Manual of Style and Usage]] |page=[https://books.google.com/books?id=CnwIVkAQgFwC&pg=PA263 263] |via=Google Books |publisher=Three Rivers Press |date=1999}}</ref>

Possessive plurals that also include apostrophes for mere pluralization and periods appear especially complex: for example, "the C.D.'s' labels" (the labels of the compact discs). In some instances, however, an apostrophe may increase clarity: for example, if the final letter of an abbreviation is "S", as in "SOS's" (although abbreviations ending with S can also take "-es", e.g. "SOSes"), or when pluralizing an abbreviation that has periods.<ref>{{cite web |url= http://www.writersblock.ca/tips/monthtip/tipmar96.htm |title=Writer's Block&nbsp;– Writing Tips&nbsp;– Plural and Possessive Abbreviations |publisher=WritersBlock.ca |access-date=September 16, 2010 |archive-url= https://web.archive.org/web/20100726124408/http://www.writersblock.ca/tips/monthtip/tipmar96.htm |archive-date=July 26, 2010}}</ref><ref>{{cite web |url= http://www.editfast.com/english/grammar/apostrophes/apostrophe_plurals.htm |title=EditFast Grammar Resource: Apostrophes: Forming Plurals |publisher=Editfast.com |access-date=September 16, 2010 |archive-url= https://web.archive.org/web/20101027001351/http://editfast.com/english/grammar/apostrophes/apostrophe_plurals.htm |archive-date=October 27, 2010 }}</ref>

A particularly rich source of options arises when the plural of an acronym would normally be indicated in a word other than the final word if spelled out in full. A classic example is "Member of Parliament", which in plural is "Members of Parliament". It is possible then to abbreviate this as "M's P", which was fairly common in mid-twentieth-century Australian news writing<ref>{{cite web |url= https://trove.nla.gov.au/work/26924909 |title=Libraries Australia&nbsp;– T.H. McWilliam, Charles Kingsford Smith, Prime Minister of New Zealand Joseph Coates, Charles Ulm and H.A. Litchfield in front row with Members of Parliament on steps of Parliament House, Wellington, New Zealand, September 1928 |at=Notes |work=NLA.gov.au |publisher=[[National Library of Australia]] |access-date=September 16, 2010 |archive-url= https://web.archive.org/web/20080622132412/http://nla.gov.au/anbd.bib-an41354070 |archive-date=June 22, 2008 |url-status= live}}</ref><ref>{{cite web |first=Robin |last=Hyde |url= https://nzetc.victoria.ac.nz/tm/scholarly/tei-HydJour-t1-body-d3.html |title=Chapter III.&nbsp;— The House is in Session |publisher=NZETC |access-date=September 16, 2010 |archive-url= https://web.archive.org/web/20110430012333/https://nzetc.victoria.ac.nz/tm/scholarly/tei-HydJour-t1-body-d3.html |archive-date=April 30, 2011 |url-status=live}}</ref> (or similar),<ref>{{cite web |url= http://www.middlemiss.org/lit/authors/denniscj/backblockother/underpartyplan.html |title=Under the party plan |first=C. J. |last=Dennis |author-link=C. J. Dennis |work=[[The Bulletin (Australian periodical)|The Bulletin]] |date=January 18, 1912 |page=43 |via=Middlemiss.org |access-date=September 16, 2010 |archive-url= https://web.archive.org/web/20100822175445/http://www.middlemiss.org/lit/authors/denniscj/backblockother/underpartyplan.html |archive-date=August 22, 2010 |url-status=live}}</ref> and used by former Australian Prime Minister [[Ben Chifley]].<ref>{{cite news |url= https://trove.nla.gov.au/newspaper/page/5605107 |via=Trove.NLA.gov.au |title=M's.P. Suffer Loss and Insecurity |date=December 2, 1948 |work=[[Townsville Bulletin|Townsville Daily Bulletin]] |page=1}}</ref><ref>{{cite news |url= https://trove.nla.gov.au/newspaper/article/27755397 |date=October 14, 1948 |title=Prime Minister Asserts M's.P. Have No Immunity from 'Official Approaches' |work=[[The Mercury (Hobart)|The Mercury]] |page=2 |via=Trove.NLA.gov.au}}</ref><ref>{{cite web |url= http://www.electricscotland.com/history/australia/melbourne11.htm |title=The Royal Caledonian Society of Melbourne |via=ElectricScotland.com |access-date=January 21, 2013 |archive-url= https://web.archive.org/web/20120715091217/http://www.electricscotland.com/history/australia/melbourne11.htm |archive-date=July 15, 2012 |url-status=live}}</ref> This usage is less common than forms with "s" at the end, such as "MPs", and may appear dated or pedantic. In common usage, therefore, "weapons of mass destruction" becomes "WMDs", "prisoners of war" becomes "POWs", and "runs batted in" becomes "RBIs".<ref>{{cite book |last=Garner |first=Bryan |author-link=Bryan Garner |title=[[Garner's Modern American Usage]] |date=August 27, 2009 |publisher=Oxford University Press |location=Oxford / New York |isbn=978-0-19-538275-4 |page=638}}</ref>

Abbreviations that come from single, rather than multiple, words{{Mdash}}such as "TV" ("television"){{Mdash}}are usually pluralized without apostrophes ("two TVs"); most writers feel that the apostrophe should be reserved for the possessive ("the TV's antenna").{{citation needed|date=November 2024}}

{{anchor|pp|PP|pP|Pp|page|pages}} In some languages, the convention of doubling the letters in the acronym is used to indicate plural words: for example, the Spanish {{lang|es|EE.UU.}}, for {{lang|es|Estados Unidos}} ('United States'). This old convention is still sometimes followed for a limited number of English abbreviations, such as ''SS.'' for ''Saints'', ''pp.'' for the plural of 'pages', or ''mss.'' for ''manuscripts''.{{citation needed|date=November 2024}}

{{further|English possessive}}

===Case===
====All-caps style====
The most common [[capitalization]] scheme seen with acronyms is all-uppercase ([[all caps]]). [[Small caps]] are sometimes used to make the run of capital letters seem less jarring to the reader. For example, the style of some American publications, including the ''[[Atlantic Monthly]]'' and ''[[USA Today]]'', is to use small caps for acronyms longer than three letters;{{Citation needed|date=August 2007}} thus "U.S." and "[[Franklin D. Roosevelt|FDR]]" in normal caps, but "{{smallcaps|nato}}" in small caps. The acronyms "[[Anno Domini|AD]]" and "[[Before Christ|BC]]" are often smallcapped as well, as in: "From {{nowrap|4004 {{smallcaps|bc}} to {{smallcaps|ad}} 525}}".

====Normal case and anacronyms<span class="anchor" id="Anacronym"></span>====
Where an acronym has linguistically taken on an identity as regular word, the acronym may use normal case rules, e.g. it would appear generally in lower case, but with an initial capital when starting a sentence or when in a title. Once knowledge of the words underlying such an acronym has faded from common recall, the acronym may be termed an '''anacronym'''.<ref>{{ShorterOxfordEnglishDictionary}}</ref> Examples of anacronyms are the words "[[scuba set|scuba]]", "[[radar]]", and "[[laser]]".  The word "an''acro''nym" should not be confused with the word "[[Misnomer#Anachronym|an''achro''nym]]", which is a type of misnomer.

====Mixed-case variant====
Words derived from an acronym by affixing are typically expressed in mixed case, so the root acronym is clear. For example, "pre-WWII politics", "post-NATO world", "[[DNase]]". In some cases a derived acronym may also be expressed in mixed case. For example, "[[messenger RNA]]" and "[[transfer RNA]]" become "mRNA" and "tRNA".

====Pronunciation-dependent style and case====
Some publications choose to capitalize only the first letter of acronyms, reserving all-caps styling for initialisms, writing the pronounced acronyms "Nato" and "Aids" in mixed case, but the initialisms "USA" and "FBI" in all caps. For example, this is the style used in ''[[The Guardian]]'',<ref>{{Cite news |url= https://www.theguardian.com/styleguide |title=Styleguide |work=[[The Guardian]] |location=London |date=December 19, 2008 |quote=Use all capitals if an abbreviation is pronounced as the individual letters (an initialism): BBC, CEO, US, VAT, etc; if it is an acronym (pronounced as a word) spell out with initial capital, eg Nasa, Nato, Unicef, unless it can be considered to have entered the language as an everyday word, such as [[awol]], [[laser]] and, more recently, [[asbo]], [[pin number]] and [[sim card]]. Note that [[pdf]] and [[public limited company|plc]] are lowercase.}}</ref> and ''[[BBC News]]'' typically edits to this style (though its official style guide, dating from 2003, still recommends all-caps<ref>{{Cite news|url= http://www.bbctraining.com/pdfs/newsstyleguide.pdf |title=BBC News Style Guide |work=BBCTraining.com |publisher=[[BBC]] |archive-url= https://web.archive.org/web/20110707214856/http://www.bbctraining.com/pdfs/newsStyleGuide.pdf |archive-date=July 7, 2011}}</ref>). The logic of this style is that the pronunciation is reflected graphically by the capitalization scheme. However, it conflicts with conventional English usage of first-letter upper-casing as a marker of proper names in many cases; e.g. ''AIDS'' stands for ''acquired immuno-deficiency syndrome'' which is not a proper name, while ''Aids'' is in the style of one.

Some style manuals also base the letters' [[Letter case|case]] on their number. ''[[The New York Times]]'', for example, keeps "NATO" in all capitals (while several guides in the British press may render it "Nato"), but uses lower case in "[[United Nations Children's Fund|Unicef]]" (from "United Nations International Children's Emergency Fund") because it is more than four letters, and to style it in caps might look ungainly (flirting with the appearance of "shouting capitals").

===Numerals and constituent words===
While abbreviations typically exclude the initials of short [[function word]]s (such as "and", "or", "of", or "to"), this is not always the case. Sometimes function words are included to make a pronounceable acronym, such as CORE ([[Congress of Racial Equality]]). Sometimes the letters representing these words are written in lower case, such as in the cases of "TfL" ("[[Transport for London]]") and ''LotR'' (''[[The Lord of the Rings]]''); this usually occurs when the acronym represents a multi-word proper noun.

Numbers (both [[cardinal number|cardinal]] and [[ordinal number|ordinal]]) in names are often represented by [[numerical digit|digit]]s rather than initial letters, as in "4GL" ("[[fourth generation language]]") or "G77" ("[[Group of 77]]"). Large numbers may use [[SI prefix#Use outside SI|metric prefixes]], as with "Y2K" for "Year 2000". Exceptions using initials for numbers include "[[three letter acronym|TLA]]" ("three-letter acronym/abbreviation") and "GoF" ("[[Gang of Four (software)|Gang of Four]]"). Abbreviations using numbers for other purposes include repetitions, such as "[[A2DP]]" ("Advanced Audio Distribution Profile"), "[[W3C]]" ("World Wide Web Consortium"), and ''[[WVOX#Notable Past Programming|T3]]'' (''Trends, Tips & Tools for Everyday Living''); pronunciation, such as "[[Business-to-business|B2B]]" ("business to business"); and [[numeronym]]s, such as "i18n" ("internationalization"; "18" represents the 18 letters between the initial "i" and the final "n").

===Casing of expansions===
Authors of [[expository writing]] will sometimes capitalize or otherwise distinctively format the initials of the expansion for [[pedagogical]] emphasis (for example, writing: "the onset of Congestive Heart Failure (CHF)" or "the onset of '''c'''ongestive '''h'''eart '''f'''ailure (CHF)"). Capitalization like this, however, conflicts with the convention of English orthography, which generally reserves capitals in the middle of sentences for proper nouns; when following the [[AMA Manual of Style]], this would instead be rendered as "the onset of congestive heart failure (CHF)".<ref name="AMA10p442">{{Citation |editor-last=Iverson |editor-first=Cheryl |display-editors=etal |title=AMA Manual of Style |edition=10th |publisher=[[Oxford University Press]] |location=Oxford, Oxfordshire |year=2007 |isbn=978-0-19-517633-9 |page=[https://archive.org/details/amamanualofstyle0000unse/page/442 442]}}</ref>

==Changes to (or wordplay on) the expanded meaning==
=== Pseudo-acronyms and orphan initialisms<span class="anchor" id="Pseudo-acronyms"></span><span class="anchor" id="Orphan initialisms"></span><!--redirects to this section -->===
Some apparent acronyms or other abbreviations do not stand for anything and cannot be expanded to some meaning. Such pseudo-acronyms may be pronunciation-based, such as "BBQ" (''bee-bee-cue''), for "barbecue", and "K9" (''kay-nine'') for "canine". Pseudo-acronyms also frequently develop as "orphan initialisms": an existing acronym is redefined as a non-acronymous name, severing its link to its previous meaning.<ref name=upenn>{{cite web |url= http://itre.cis.upenn.edu/~myl/languagelog/archives/003555.html |work=[[Language Log]] |title=Orphan Initialisms |date=September 7, 2006 |first=Arnold |last=Zwicky |author-link=Arnold Zwicky |editor-first=Mark |editor-last=Liberman |editor-link=Mark Liberman |publisher=University of Pennsylvania |access-date=September 27, 2010 |archive-url= https://web.archive.org/web/20100621181657/http://itre.cis.upenn.edu/~myl/languagelog/archives/003555.html |archive-date=June 21, 2010 |url-status=live}}</ref><ref name=about>[http://grammar.about.com/b/2010/06/02/what-does-bp-stand-for.htm What Does "BP" Stand For?] {{webarchive |url= https://web.archive.org/web/20121118220424/http://grammar.about.com/b/2010/06/02/what-does-bp-stand-for.htm |date=November 18, 2012}}</ref> For example, the letters of the "[[SAT]]", a US college entrance test originally dubbed "Scholastic Aptitude Test", no longer officially stand for anything.<ref>{{cite news |url= https://www.nytimes.com/1997/04/02/us/insisting-it-s-nothing-creator-says-sat-not-sat.html |title=Insisting It's Nothing, Creator Says SAT, Not S.A.T. |newspaper=[[The New York Times]] |date=April 2, 1997 |last=Applebome |first=Peter |access-date=February 14, 2017 |archive-url= https://web.archive.org/web/20170417203501/http://www.nytimes.com/1997/04/02/us/insisting-it-s-nothing-creator-says-sat-not-sat.html |archive-date=April 17, 2017 |url-status=live}}</ref><ref>{{Cite news |title= Changes to SAT Make Test More Coachable |last=Komarek |first=Dan |newspaper=[[Daily Californian]] |date=July 29, 2003}}</ref> The US-based [[Abortion-rights movements|abortion-rights]] organization "[[NARAL Pro-Choice America|NARAL]]" was another example of this; in that case, the organization changed its name several times, with the long-form of the name always corresponding to the letters "NARAL", later opting to simply be known by the short-form, without being connected to a long-form, and finally dropping the term to become [[Reproductive Freedom for All]].

This is common with companies that want to retain [[brand recognition]] while moving away from an outdated image: American Telephone and Telegraph became [[AT&T Corporation|AT&T]]<ref name=upenn /> and [[BP|British Petroleum]] became BP.<ref name=about /><ref>{{cite web |url= http://www.corporatewatch.org/?lid=287 |title=BP plc History |access-date=September 29, 2010 |archive-url= https://web.archive.org/web/20100615011613/http://www.corporatewatch.org/?lid=287 |archive-date=June 15, 2010 |url-status=live}}</ref> ''[[RT (TV network)|Russia Today]]'' has rebranded itself as ''RT''. [[American Movie Classics]] has simply rebranded itself as AMC. [[Genzyme Transgenics Corporation]] became GTC Biotherapeutics, Inc.; [[The Learning Channel]] became TLC; [[MTV]] dropped the name Music Television out of its brand; and [[American District Telegraph]] became simply known as ADT. "[[KFC|Kentucky Fried Chicken]]" went partway, re-branding itself with its initialism "KFC" to de-emphasize the role of frying in the preparation of its signature dishes, though they have since returned to using both interchangeably.<ref>{{cite news |url= http://findarticles.com/p/articles/mi_m3190/is_n8_v25/ai_10403447 |title=KFC shuns 'fried' image with new name&nbsp;– Kentucky Fried Chicken has changed its name to KFC |first=Peter O. |last=Keegan |publisher=Nation's Restaurant News |date=February 21, 1991 |access-date=August 24, 2007 |archive-url= https://web.archive.org/web/20071104124859/http://findarticles.com/p/articles/mi_m3190/is_n8_v25/ai_10403447 |archive-date=November 4, 2007 |url-status=live}}</ref>{{efn|This change was also applied to other languages, with ''Poulet Frit Kentucky'' becoming ''PFK'' in French Canada.}} The East Coast Hockey League became the [[ECHL]] when it expanded to include cities in the western United States prior to the 2003–2004 season.

Pseudo-acronyms may have advantages in international markets: for example, some national [[Affiliate (commerce)|affiliates]] of [[International Business Machines]] are legally incorporated with "IBM" in their names (for example, IBM Canada) to avoid translating the full name into local languages.{{citation needed|date=October 2017}} Likewise, [[UBS AG|UBS]] is the name of the merged [[Union Bank of Switzerland]] and [[Swiss Bank Corporation]],<ref>[https://www.telegraph.co.uk/finance/2833426/UBS-means-RIP-for-Warburg.html UBS means RIP for Warburg] {{Webarchive|url= https://web.archive.org/web/20180504225347/https://www.telegraph.co.uk/finance/2833426/UBS-means-RIP-for-Warburg.html |date=May 4, 2018}}. ''[[The Daily Telegraph]]'', November 13, 2002</ref> and [[HSBC]] has replaced the long name Hongkong and Shanghai Banking Corporation. Some companies which have a name giving a clear indication of their place of origin will choose to use acronyms when expanding to foreign markets: for example, [[Toronto-Dominion Bank]] sometimes continues to operate under its full name in Canada, but its U.S. subsidiary is known only as [[TD Bank, N.A.|TD Bank]], just as [[Royal Bank of Canada]] sometimes still uses its full name in Canada (a [[constitutional monarchy]]) while its U.S. subsidiary is always only called [[RBC Bank]]. The India-based [[JSW Group]] of companies is another example of the original name (Jindal South West Group) being re-branded into a pseudo-acronym while expanding into other geographical areas in and outside of India.

===Redundant acronyms and RAS syndrome===
{{Main|RAS syndrome}}
{{Multiple issues|section=yes|
{{Unreferenced section|date=October 2017}}
{{Original research section|date=October 2017}}
}}
Rebranding can lead to [[RAS syndrome|redundant acronym syndrome]], as when [[Trustee Savings Bank]] became TSB Bank, or when [[Railway Express Agency]] became REA Express. A few [[high-tech]] companies have taken the redundant acronym to the extreme: for example, ISM Information Systems Management Corp. and SHL Systemhouse Ltd. Examples in entertainment include the television shows ''[[CSI: Crime Scene Investigation]]'' and ''[[NCIS (TV series)|Navy: NCIS]]'' ("Navy" was dropped in the second season), where the redundancy was likely designed to educate new viewers as to what the initials stood for. The same reasoning was in evidence when the [[Royal Bank of Canada]]'s Canadian operations rebranded to RBC Royal Bank, or when [[Bank of Montreal]] rebranded their retail banking subsidiary BMO Bank of Montreal.

Another common example is "[[random-access memory|RAM]] memory", which is redundant because "RAM" ("random-access memory") includes the initial of the word "memory". "PIN" stands for "personal identification number", obviating the second word in "[[Personal identification number|PIN]] number"; in this case its retention may be motivated to avoid ambiguity with the homophonous word "pin". Other examples include "[[automated teller machine|ATM]] machine", "[[European American Bank|EAB]] bank", "HIV virus", Microsoft's [[Windows NT|NT]] Technology, and the formerly redundant "[[SAT]] test", now simply "SAT Reasoning Test"). [[Spike (TV network)|TNN]] (The Nashville/National Network) also renamed itself "The New TNN" for a brief interlude.

===Redefined acronyms===
In some cases, while the initials in an acronym may stay the same, for what those letters stand may change. Examples include the following:

*DVD was originally an acronym for the unofficial term "digital video disc", but is now stated by the [[DVD Forum]] as standing for "Digital Versatile Disc"{{citation needed|date=August 2022}}
*[[Government Accountability Office|GAO]] changed the full form of its name from "General Accounting Office" to "Government Accountability Office"<ref>{{cite web|title=100 Years of GAO|publisher=U.S. Government Accountability Office|url= https://www.gao.gov/about/what-gao-does/hundred-years-of-gao|access-date=August 7, 2022}}</ref>
*[[United States Government Publishing Office|GPO]] changed the full form of its name from "Government Printing Office" to "Government Publishing Office"<ref>{{cite web|title=History|publisher=U.S. Government Publishing Office|url= https://www.gpo.gov/who-we-are/our-agency/history|access-date=August 7, 2022}}</ref>
*[[RAID]] was originally an acronym for "Redundant Array of Inexpensive Disks" but has since been redefined as "Redundant Array of Independent Disks"<ref>"Originally referred to as Redundant Array of Inexpensive Disks, the term RAID was first published in the late 1980s by Patterson, Gibson, and Katz of the University of California at Berkeley. (The RAID Advisory Board has since substituted the term Inexpensive with Independent.)" ''Storage Area Network Fundamentals''; Meeta Gupta; Cisco Press; {{ISBN|978-1-58705-065-7}}; Appendix A.</ref>
*The [[Union for International Cancer Control|UICC]] was founded as the "International Union Against Cancer",<ref>{{cite web|title=History of UICC (up to late 1960s)|publisher=UICC|url= https://www.uicc.org/sites/main/files/atoms/files/History-of-UICC-Late-1960s.pdf|access-date=August 7, 2022}}</ref> and its initials originally came from the [[Romance languages|Romance-language]] versions of that name (such as French {{lang|fr|Union Internationale Contre le Cancer}}). The English expansion of its name has since been changed to "Union for International Cancer Control" so that it would also correspond to the UICC acronym.
*[[World Wide Fund for Nature|WWF]] was originally an acronym for "World Wildlife Fund", but now stands for "World Wide Fund for Nature" (although the organization's branches in the U.S. and Canada still use the original name)<ref>{{cite web |title=World Wide Fund for Nature |publisher=World Wildlife Fund |date=2018 |url= https://help.worldwildlife.org/hc/en-us/articles/360008012153-World-Wide-Fund-for-Nature |access-date=August 7, 2022}}</ref>

===Backronyms===
{{Main|Backronym}}
A ''backronym'' (or ''bacronym'') is a [[phrase]] that is constructed "after the fact" from a previously existing word. For example, the novelist and critic [[Anthony Burgess]] once proposed that the word "book" ought to stand for "box of organized knowledge".<ref>''99 Novels: The Best in English Since 1939'' (New York: Summit Books, 1984).</ref> A classic real-world example of this is the name of the predecessor to the Apple Macintosh, the [[Apple Lisa]], which was said to refer to "Local Integrated Software Architecture", but was actually named after Steve Jobs' daughter, born in 1978.

===Contrived acronyms===
{{Tone|section|date=January 2024}}
Acronyms are sometimes [[wikt:contrive#Verb|contrived]], that is, deliberately designed to be especially apt for the thing being named (by having a dual meaning or by borrowing the positive connotations of an existing word). Some examples of contrived acronyms are ''[[Patriot Act|USA PATRIOT]]'', [[Can Spam Act|''CAN SPAM'']], ''[[CAPTCHA]]'' and ''[[AIDS Coalition to Unleash Power|ACT UP]]''.{{Citation needed|date=January 2018}} The clothing company [[French Connection (clothing)|French Connection]] began referring to itself as ''fcuk'', standing for "French Connection United Kingdom". The company then created T-shirts and several advertising campaigns that exploit the acronym's similarity to the taboo word "[[fuck]]". Contrived acronyms find frequent use as names of [[list of fictional espionage organizations|fictional agencies]], with a famous example being frequent [[James Bond]] antagonist organization [[SPECTRE]] (SPecial Executive for Counterintelligence, Terrorism, Revenge and Extortion).

The [[United States Department of Defense|U.S. Department of Defense]]'s Defense Advanced Research Projects Agency ([[DARPA]]) is known for developing contrived acronyms to name projects, including ''RESURRECT'', ''NIRVANA'', and ''DUDE''. In July 2010, ''[[Wired (magazine)|Wired]]'' magazine reported that DARPA announced programs to "transform biology from a descriptive to a predictive field of science" named ''BATMAN'' and ''ROBIN'' for "Biochronicity and Temporal Mechanisms Arising in Nature" and "Robustness of Biologically-Inspired Networks",<ref>{{cite magazine |url= https://www.wired.com/dangerroom/2010/07/holy-acronym-darpa-batman-robin-to-master-biology-outdo-evolution/ |title=Holy Acronym, Darpa! 'Batman & Robin' to Master Biology, Outdo Evolution |first=Katie |last=Drummond |magazine=[[Wired (magazine)|Wired]] |date=July 6, 2010 |access-date=March 5, 2017 |archive-url= https://web.archive.org/web/20130702073147/http://www.wired.com/dangerroom/2010/07/holy-acronym-darpa-batman-robin-to-master-biology-outdo-evolution/ |archive-date=July 2, 2013 |url-status=live}}</ref> a reference to comic-book superheroes [[Batman]] and [[Robin (comics)|Robin]].

The short-form [[Clinical trial naming conventions|names of clinical trials]] and other scientific studies constitute a large class of acronyms that includes many contrived examples, as well as many with a partial rather than complete correspondence of letters to expansion components. These trials tend to have full names that are accurately descriptive of what the trial is about but are thus also too long to serve practically as names within the syntax of a sentence, so a short name is also developed, which can serve as a syntactically useful handle and also provide at least a degree of [[mnemonic]] reminder as to the full name. Examples widely known in medicine include the ALLHAT trial (Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial) and the CHARM trial (Candesartan in Heart Failure: Assessment of Reduction in Mortality and Morbidity). The fact that [[RAS syndrome]] is often involved, as well as that the letters often do not entirely match, have sometimes been pointed out by annoyed researchers preoccupied by the idea that because the [[Archetype|archetypal]] form of acronyms originated with one-to-one letter matching, there must be some impropriety in their ever deviating from that form. However, the purpose of clinical trial acronyms, as with [[Gene nomenclature#Symbol and name|gene and protein symbols]], is simply to have a syntactically usable and easily [[Recall (memory)|recalled]] short name to complement the long name that is often syntactically unusable and not [[Memorization|memorized]]. It is useful for the short name to give a reminder of the long name, which supports the reasonable censure of "cutesy" examples that provide little to no hint of it. But beyond that reasonably close correspondence, the short name's chief utility is in functioning cognitively as a name, rather than being a [[wikt:cryptic#Adjective|cryptic]] and forgettable string, albeit faithful to the matching of letters. However, other reasonable critiques have been (1) that it is irresponsible to mention trial acronyms without explaining them at least once by providing the long names somewhere in the document,<ref name="PMID-12767559">{{Citation |last=Cheng |first=Tsung O |year=2003 |title=No more unexplained trial acronyms please. Trial Acronyms: Better Obvious than Obscure (TABOO) |journal=Int J Cardiol |volume=89 |issue=2–3 |page=303 |pmid=12767559 |doi=10.1016/S0167-5273(02)00411-4}}</ref> and (2) that the proliferation of trial acronyms has resulted in ambiguity, such as three different trials all called ASPECT, which is another reason why failing to explain them somewhere in the document is irresponsible in scientific communication.<ref name="PMID-12767559" /> At least one study has evaluated the [[citation impact]] and other traits of acronym-named trials compared with others,<ref name="PMID-16823008">{{cite journal |last1=Stanbrook |first1=M. B. |last2=Austin |first2=P. C. |last3=Redelmeier |first3=D. A. |date=2006 |title=Acronym-named randomized trials in medicine—the ART in medicine study |journal=[[New England Journal of Medicine]] |volume=355 |issue=1 |pages=101–102 |pmid=16823008 |doi=10.1056/NEJMc053420}}</ref> finding both good aspects (mnemonic help, name recall) and potential flaws ([[Connotation|connotatively]] driven [[bias]]).<ref name="PMID-16823008" />

Some acronyms are chosen deliberately to avoid a name considered undesirable: For example, {{lang|de|[[Verliebt in Berlin]]}} (''ViB''), a German [[telenovela]], was first intended to be {{lang|de|Alles nur aus Liebe}} ('All for Love'), but was changed to avoid the resultant acronym ''[[Anus|ANAL]]''. Likewise, the Computer Literacy and Internet Technology qualification is known as ''CLaIT'',<ref name="CIE.org.uk_CLaIT">{{cite web |title=CLAiT–International |work=CIE.org |publisher=[[University of Cambridge]] |url= http://www.cie.org.uk/qualifications/vocational/clait/overview |archive-url= https://web.archive.org/web/20120114062047/http://www.cie.org.uk/qualifications/vocational/clait/overview |archive-date=January 14, 2012}}</ref> rather than ''[[Clitoris|CLIT]]''. In Canada, the [[Canadian Alliance|Canadian Conservative Reform Alliance (Party)]] was quickly renamed to the "Canadian Reform Conservative Alliance" when its opponents pointed out that its initials spelled CCRAP (pronounced "see [[Feces|crap]]"). Two Irish institutes of technology (Galway and Tralee) chose different acronyms from other institutes when they were upgraded from regional technical colleges. Tralee RTC became the Institute of Technology Tralee (ITT), as opposed to Tralee Institute of Technology ([[Breast|TIT]]). Galway RTC became Galway-Mayo Institute of Technology (GMIT), as opposed to Galway Institute of Technology ([[wikt:git|GIT]]). The charity sports organization [[Leukemia & Lymphoma Society#Fundraising|Team in Training]] is known as "TNT" and not "TIT". [[Technological Institute of Textile & Sciences]], however, is still known as "TITS". [[George Mason University]] was planning to name their law school the "Antonin Scalia School of Law" ([[Asshole|ASSOL]]) in honor of the late [[Antonin Scalia]], only to change it to the "[[Antonin Scalia Law School]]" later.<ref>{{cite news |url= https://www.npr.org/2016/04/07/473339332/unfortunate-acronym-forces-law-school-name-change |title=Unfortunate Acronym Forces Law School Name Change |work=[[Morning Edition]] |publisher=[[NPR]] |date=April 7, 2016 |access-date=April 4, 2018 |archive-url= https://web.archive.org/web/20181219044112/https://www.npr.org/2016/04/07/473339332/unfortunate-acronym-forces-law-school-name-change |archive-date=December 19, 2018 |url-status=live}}</ref>

===Macronyms/nested acronyms===
{{Multiple issues|section=yes|{{More citations needed section|date=February 2020}}
{{Original research section|date=February 2020}}}}
A '''macronym''', or '''nested acronym''', is an acronym in which one or more letters stand for acronyms (or abbreviations) themselves. The word "macronym" is a [[portmanteau]] of "[[wikt:macro-|macro-]]" and "acronym".

Some examples of macronyms are:<!-- with citations in each individual article's references -->
* [[XMLHttpRequest|XHR]] stands for "XML HTTP Request", in which "[[XML]]" is "Extensible Markup Language", and [[HTTP]] stands for "HyperText Transfer Protocol"
* [[IBM Power microprocessors|POWER]] stands for "Performance Optimization With Enhanced RISC", in which "[[RISC]]" stands for "reduced instruction set computer"
* [[VHDL]] stands for "VHSIC Hardware Description Language", in which "[[VHSIC]]" stands for "Very High Speed Integrated Circuit"
* [[XSD]] stands for "XML Schema Definition", in which "[[XML]]" stands for "Extensible Markup Language"
* [[AOL Instant Messenger|AIM]] stands for "AOL Instant Messenger", in which "[[AOL]]" originally stood for "America Online"
* [[Houston Automatic Spooling Priority|HASP]] stood for "Houston Automatic Spooling Priority", but "[[spooling]]" itself was an acronym: "simultaneous peripheral operations on-line"
* [[VORTAC]] stands for "VOR+TACAN", in which "VOR" is "[[VHF omnidirectional range]]" (where VHF = very high frequency radio) and "TAC" is short for [[TACAN]], which stands for "tactical air navigation"
* [[Global Information Assurance Certification]] has a number of nested acronyms for its certifications, e.g. "GSEC" is an acronym for "GIAC Security Essentials"
* [[REM behaviour disorder|RBD]] stands for "REM Behavior Disorder", in which "[[Rapid eye movement sleep|REM]]" stands for "rapid eye movement"

Some macronyms can be multiply nested: the second-order acronym points to another one further down a hierarchy. [[VHDL-VITAL|VITAL]], for example, which expands to "[[VHDL]] Initiative Towards [[ASIC]] Libraries" is a total of 15 words when fully expanded. In an informal competition run by the magazine ''[[New Scientist]]'', a fully documented specimen was discovered that may be the most deeply nested of all: RARS is the "Regional ATOVS Retransmission Service"; ATOVS is "Advanced TOVS"; TOVS is "[[TIROS]] operational vertical sounder"; and TIROS is "Television infrared observational satellite".<ref>{{cite web|url= https://www.newscientist.com/article/mg20727681.100-very-deep-multiply-nested-acronyms.html |title=Very deep multiply nested acronyms |work=[[New Scientist]] |date=July 7, 2010 |access-date=September 16, 2010 |archive-url= https://web.archive.org/web/20100914033751/http://www.newscientist.com/article/mg20727681.100-very-deep-multiply-nested-acronyms.html |archive-date=September 14, 2010 |url-status=live}}</ref> Fully expanded, "RARS" might thus become "Regional Advanced Television Infrared Observational Satellite Operational Vertical Sounder Retransmission Service", which would produce the much more unwieldy acronym "RATIOSOVSRS".

However, to say that "RARS" stands directly for that string of words, or can be interchanged with it in [[syntax]] (in the same way that "CHF" can be usefully interchanged with "congestive heart failure"), is a [[Linguistic prescription|prescriptive]] misapprehension rather than a linguistically accurate description; the true nature of such a term is closer to [[#All-caps style|anacronymic]] than to being interchangeable like simpler acronyms are. The latter are fully reducible in an attempt to "spell everything out and avoid all abbreviations", but the former are irreducible in that respect; they can be [[Gloss (annotation)|annotated]] with parenthetical explanations, but they cannot be eliminated from speech or writing in any useful or practical way. Just as the words ''laser'' and ''radar'' function as words in [[syntax]] and [[cognition]] without a need to focus on their acronymic origins, terms such as "RARS" and "[[CHA2DS2–VASc score]]" are irreducible in [[natural language]]; if they are purged, the form of language that is left may conform to some imposed rule, but it cannot be described as remaining natural. Similarly, [[protein]] and [[gene]] nomenclature, [[Gene nomenclature#Symbol and name|which uses symbols extensively]], includes such terms as the name of the [[NACHT domain|NACHT protein domain]], which reflects the symbols of some proteins that contain the domain – NAIP (NLR family apoptosis [[inhibitor protein]]), C2TA (major histocompatibility complex class II transcription activator), HET-E (incompatibility locus protein from ''Podospora anserine''), and TP1 (telomerase-associated protein) – but is not syntactically reducible to them. The name is thus itself more symbol than acronym, and its expansion cannot replace it while preserving its function in natural syntax as a name within a [[clause]] clearly [[Parsing|parsable]] by human readers or listeners.

====Recursive acronyms====
{{Main|Recursive acronym}}
A special type of macronym, the [[recursive acronym]], has letters whose expansion refers back to the macronym itself. One of the earliest examples appears in ''[[The Hacker's Dictionary]]'' as [[Mung (computer term)|MUNG]], which stands for "MUNG Until No Good".

Some examples of recursive acronyms are:
* [[GNU]] stands for "GNU's Not Unix!"
* [[LAME]] stands for "LAME Ain't an MP3 Encoder"
* [[PHP]] stands for "PHP: Hypertext Preprocessor"
* [[Wine (software)|WINE]] stands for "WINE Is Not an Emulator"
* [[GNU Hurd|HURD]] stands for "HIRD of Unix-replacing daemons", where HIRD itself stands for "HURD of interfaces representing depth" (a "mutually recursive" acronym)

==Non-English languages==
===Specific languages===
====Chinese====
With English terminology, discussions of languages with [[syllabary|syllabic]] or [[logographic]] writing systems (such as Chinese, Japanese, and Korean), "acronyms" describe the short forms that take selected characters from a multi-character word.

For example, in Chinese, 'university' ({{lang|zh-hant|大學}}/{{lang|zh-hans|大学}}, {{literally|great learning}}) is usually abbreviated simply as {{lang|zh|大}} ('great') when used with the name of the institute. So '[[Peking University]]' ({{lang|zh-hans|北京大学}}) is commonly shortened to {{lang|zh|北大}} ({{abbr|lit.|literally}} 'north-great') by also only taking the first character of ''Peking'', the "northern capital" ({{lang-zh|c=北京|p=Beijing|labels=no}}). In some cases, however, other characters than the first can be selected. For example, the local short form of '[[Hong Kong University]]' ({{lang|zh-hant|香港大學}}) uses {{lang|zh-Latn|Kong}} ({{lang|zh-hant|港大}}) rather than {{lang|zh-Latn|Hong}}.{{citation needed|date=September 2025}}

====Korean====
Many aspects of academics in Korea follow similar acronym patterns as Chinese, owing to the two languages' commonalities, like using the word for 'big' or 'great' i.e. {{lang|ko-Latn|dae}} ({{lang|ko-Hang|대}}), to refer to universities ({{lang|ko-Hang|대학}}; {{lang|ko-Latn|daehak}}, literally 'great learning' although 'big school' is an acceptable alternate). They can be interpreted similarly to American university appellations, such as "UPenn" or "Texas Tech".

Some acronyms are shortened forms of the school's name, like how [[Hongik University]] ({{lang|ko-Hang|홍익대학교}}, {{lang|ko-Latn|Hongik Daehakgyo}}) is shortened to {{lang|ko-Latn|Hongdae}} ({{lang|ko-Hang|홍대}}, 'Hong, the big [school]' or 'Hong-U') Other acronyms can refer to the university's main subject, e.g. [[Korea National University of Education]] ({{lang|ko-Hang|한국교원대학교}}, {{lang|ko-Latn|Hanguk Gyowon Daehakgyo}}) is shortened to {{lang|ko-Latn|Gyowondae}} (교원대, 'Big Ed.' or 'Ed.-U'). Other schools use a Koreanized version of their English acronym. The [[KAIST|Korea Advanced Institute of Science and Technology]] ({{lang|ko-Hang|한국과학기술원}}, {{lang|ko-Latn|Hanguk Gwahak Gisulwon}}) is referred to as KAIST ({{lang|ko-Hang|카이스트}}, {{lang|ko-Latn|Kaiseuteu}}) in both English and Korean. The 3 most prestigious schools in Korea are known as SKY ({{lang|ko|스카이}}, {{lang|ko-Latn|seukai}}), combining the first letter of their English names ('''S'''eoul National, '''K'''orea, and '''Y'''onsei Universities). In addition, the College Scholastic Ability Test ({{lang|ko-Hang|대학수학능력시험}}, {{lang|ko-Latn|Daehak Suhang Neungryeok Siheom}}) is shortened to {{lang|ko-Latn|Suneung}} ({{lang|ko-Hang|수능}}, 'S.A.').

====Japanese====
{{main|Japanese abbreviated and contracted words}}
The Japanese language makes extensive use of abbreviations, but only some of these are acronyms.

Chinese-based words ([[Sino-Japanese vocabulary]]) use similar acronym formation to Chinese, like {{nihongo|''Tōdai''|東大}} for {{nihongo|''Tōkyō Daigaku''|東京大学|Tokyo University}}. It is not always the case that the first character of each word is used, as in [[Saikyō Line|Saikyō]] for 埼京, from {{nihongo|''[[Saitama, Saitama|Saitama]]'' + ''[[Tokyo|Tōkyō]]''|埼玉＋東京}}, which uses the second character of 東京.

Non-Chinese foreign borrowings ([[gairaigo]]) are instead frequently abbreviated as [[clipped compound]]s, rather than acronyms, using several initial sounds. This is visible in [[katakana]] transcriptions of foreign words, but is also found with native words (written in [[hiragana]]). For example, the ''[[Pokémon]]'' media franchise's name originally stood for "pocket monsters" ({{lang|ja-Kana|'''ポケ'''ット·'''モン'''スター}} [po-ke-tto-mon-su-tā]{{nowrap|{{space|2}}{{arrow2|r|12px}}{{space|2}}}}{{lang|ja-Kana|ポケモン}}), which is still the long-form of the name in Japanese, or "[[wāpuro]]" for "[[word processor]]" ({{lang|ja-Kana|'''ワー'''ド·'''プロ'''セッサー}} [wā-do-pu-ro-se-ssā]{{nowrap|{{space|2}}{{arrow2|r|12px}}{{space|2}}}}{{lang|ja-Kana|ワープロ}}).

====German====
To a greater degree than English does, German tends toward acronyms that use initial syllables rather than initial single letters, although it uses many of the latter type as well. Some examples of the syllabic type are {{lang|de|[[Gestapo]]}} rather than ''GSP'' (for {{lang|de|Geheime Staatspolizei}}, 'Secret State Police'); {{lang|de|Flak}} rather than ''FAK'' (for {{lang|de|Fliegerabwehrkanone}}, '[[Anti-aircraft warfare|anti-aircraft]] gun'); {{lang|de|Kripo}} rather than ''KP'' (for {{lang|de|[[Kriminalpolizei]]}}, 'detective division police'). The extension of such contraction to a pervasive or whimsical degree has been mockingly labeled {{lang|de|[[wikt:Aküfi|Aküfi]]}} (for {{lang|de|Abkürzungsfimmel}}, 'strange habit of abbreviating'). Examples of {{lang|de|Aküfi}} include {{lang|de|Vokuhila}} (for {{lang|de|vorne kurz, hinten lang}}, 'short in the front, long in the back', i.e., a [[Mullet (haircut)|mullet]] haircut) and the mocking of [[Adolf Hitler]]'s title as {{lang|de|[[Gröfaz]]}} ({{lang|de|Größter Feldherr aller Zeiten}}, 'Greatest General of all Time').

====Hebrew====
{{Main|Hebrew acronyms}}
It is common to take more than just one initial letter from each of the words composing the acronym; regardless of this, the abbreviation sign [[gershayim]] {{angle bracket|״}} is always written between the second-last and last letters of the non-inflected form of the acronym, even if by this it separates letters of the same original word. Examples (keeping in mind that Hebrew reads right-to-left): {{lang|he|ארה״ב|rtl=yes}} (for {{lang|he|ארצות הברית|rtl=yes}}, the United States); {{lang|he|ברה״מ|rtl=yes}} (for {{lang|he|ברית המועצות|rtl=yes}}, the Soviet Union); {{lang|he|ראשל״צ|rtl=yes}} (for {{lang|he|ראשון לציון|rtl=yes}}, [[Rishon LeZion]]); {{lang|he|ביה״ס|rtl=yes}} (for {{lang|he|בית הספר|rtl=yes}}, the school). An example that takes only the initial letters from its component words is {{lang|he|צה״ל|rtl=yes}} ({{lang|he-Latn|Tzahal}}, for {{lang|he|צבא הגנה לישראל|rtl=yes}}, [[Israel Defense Forces]]). In inflected forms, the abbreviation sign {{lang|he-Latn|[[gershayim]]}} remains between the second-last and last letters of the non-inflected form of the acronym (e.g. 'report', singular: {{lang|he|דו״ח|rtl=yes}}, plural: {{lang|he|דו״חות|rtl=yes}}; 'squad commander', masculine: {{lang|he|מ״כ|rtl=yes}}, feminine: {{lang|he|מ״כית|rtl=yes}}).

====Indonesian====
{{see also|List of Indonesian acronyms and abbreviations}}
There is also a widespread use of acronyms in [[Indonesia]] in every aspect of social life. For example, the {{lang|id|[[Golkar]]}} political party stands for {{lang|id|Partai Golongan Karya}}, {{lang|id|[[Monas]]}} stands for {{lang|id|Monumen Nasional}} ('National Monument'), the {{lang|id|Angkot}} public transport stands for {{lang|id|Angkutan Kota}} ([[Share taxi#Indonesia|'city public transportation']]), {{lang|id|warnet}} stands for {{lang|id|warung internet}} ('[[internet café]]'), and many others. Some acronyms are considered formal (or officially adopted), while many more are considered informal, slang, or [[colloquial]].

The capital's metropolitan area ([[Jakarta]] and its surrounding [[Satellite city|satellite regions]]), {{lang|id|[[Jabodetabek]]}}, is another acronym. This stands for {{lang|id|Jakarta-Bogor-Depok-Tangerang-Bekasi}}. Many highways are also named by the acronym method; e.g. {{lang|id|Jalan Tol}} ('Toll Road') {{lang|id|Jagorawi}} ({{lang|id|Jakarta-Bogor-Ciawi}}), {{lang|id|Purbaleunyi}} ({{lang|id|Purwakarta-Bandung-Cileunyi}}), and {{lang|id|Joglo Semar}} ({{lang|id|Jogja-Solo-Semarang}}).

In some languages, especially those that use certain [[alphabets]], many acronyms come from the governmental use, particularly in the military and law enforcement services. The [[Indonesian military]] (TNI – {{lang|id|Tentara Nasional Indonesia}}) and [[Indonesian police]] (POLRI – {{lang|id|Kepolisian Republik Indonesia}}) are known for heavy acronyms use. Examples include the {{lang|id|[[Kopassus]]}} ({{lang|id|Komando Pasukan Khusus}}; '[[Special Forces]] Command'), {{lang|id|[[Kopaska]]}} ({{lang|id|Komando Pasukan Katak}}; '[[Frogmen]] Command'), {{lang|id|Kodim}} ({{lang|id|Komando Distrik Militer}}; 'Military District Command' – one of the Indonesian army's [[administrative divisions]]), {{lang|id|Serka}} ({{lang|id|Sersan Kepala}}; 'Head [[Sergeant]]'), {{lang|id|Akmil}} ({{lang|id|Akademi Militer}}; 'Military Academy' – in [[Magelang]]), and many other terms regarding [[Military ranks|ranks]], units, divisions, procedures, etc.

==== Malay ====
Although not as common as in Indonesian, a number of Malay words are formed by merging two words, such as {{lang|ms|tadika}} from {{lang|ms|taman didikan kanak-kanak}} ('kindergarten') and {{lang|ms|pawagam}} from {{lang|ms|panggung wayang gambar}}. This, however, has been less prevalent in the modern era, in contrary to Indonesian. It is still often for names such as organisation names, among the most famous being MARA from {{lang|ms|[[Majlis Amanah Rakyat]]}} ('People's Trust Council'), a government agency in Malaysia.

Some acronyms are developed from the [[Jawi alphabet|Jawi]] (Malay in Arabic script) spelling of the name and may not reflect its Latin counterpart such as PAS from {{lang|ms|[[Malaysian Islamic Party|Parti Islam Se-Malaysia]]}} ('Malaysian Islamic Party') which originated from the Jawi acronym {{lang|ms-Arab|ڤاس from ڤرتي إسلام سمليسيا}}, with the same pronunciation, since the first letter of the word 'Islam' in Jawi uses the letter [[Aleph]], which is pronounced like the letter ''A'' when in such position as in the acronym.

Rules in writing initialisms in Malay differ based on its script. In its Latin form, the initialism would be spelt much like in English, using capitals written without any spacing, such as TNB for {{lang|ms|[[Tenaga Nasional]] Berhad}}.

In Jawi, however, initialisms differ depending on the source language. For Malay initialisms, the initial Jawi letters would be written separated by a period such as {{lang|ms-Arab|د.ب.ڤ}} for {{lang|ms-Arab|[[Dewan Bahasa dan Pustaka|ديوان بهاس دان ڤوستاک]]}}.<ref>{{Cite book |last1= bin Dahaman |first1=Ismail |last2=Ahmad |first2=Manshoor bin Haji |title=Daftar Kata Bahasa Melayu: Rumi-Sebutan-Jawi (Jilid 1) |publisher=[[Dewan Bahasa dan Pustaka]] |date=2001 |isbn=978-983-62-4672-1 |location=Kuala Lumpur |page=129 |language=ms-MY |trans-title=Malay Language Word Directory: Rumi-Pronunciation-Jawi (Book 1)}}</ref> If the initialism is from a different language, however, it would be written by transliterating each letter from the original language, such as {{lang|ms-Arab|عيم.سي.عيم.سي.}} for [[Malaysian Communications and Multimedia Commission|MCMC]], or {{lang|ms-Arab|الفا.ڤي.ثيتا}} for [[Aristotle University of Thessaloniki|Α.Π.Θ.]]<ref>{{cite web |url= https://fdocuments.in/document/report-for-malaysias-internationalized-domain-cssescwaorglbictd096001pdfreport.html |title=Report for Malaysia's Internationalized Domain Name: Jawi Language Issues |publisher=MYNIC Berhad |date=December 3, 2009 |via=FDocuments.in}}</ref>

====Russian====
Acronyms that use parts of words (not necessarily syllables) are commonplace in Russian as well, e.g. {{lang|ru|Газпром}} ({{lang|ru-Latn|[[Gazprom]]}}), for {{lang|ru|Газовая промышленность}} ({{transliteration|ru|Gazovaya promyshlennost}}, 'gas industry'). There are also initialisms, such as {{lang|ru|СМИ}} ('SMI', for {{lang|ru|средства массовой информации}} {{transliteration|ru|sredstva massovoy informatsii}}, 'means of mass informing'; {{lang|ru|ГУЛаг}} ({{lang|ru-Latn|[[GULag]]}}) combines two initials and three letters of the final word: it stands for {{lang|ru|Главное управление лагерей}} ({{transliteration|ru|Glavnoe upravlenie lagerey}}, 'Chief Administration of Camps').

Historically, ''[[OTMA]]'' was an acronym sometimes used by the daughters of Emperor [[Nicholas II of Russia]] and his consort, [[Alexandra Feodorovna (Alix of Hesse)|Alexandra Feodorovna]], as a group nickname for themselves, built from the first letter of each girl's name in the order of their births: Olga, Tatiana, Maria, and Anastasia.

====Swahili====
In [[Swahili language|Swahili]], acronyms are common for naming organizations such as ''TUKI'', which stands for {{lang|sw|Taasisi ya Uchunguzi wa Kiswahili}} ('Institute for Swahili Research'). Multiple initial letters (often the initial syllable of words) are often drawn together, as seen more in some languages than others.

====Vietnamese====
In [[Vietnamese language|Vietnamese]], which has an abundance of compound words, initialisms are very commonly used for both proper and common nouns. Examples include ''TP.HCM'' ({{lang|vi|Thành phố Hồ Chí Minh}}, '[[Ho Chi Minh City]]'), ''THPT'' ({{lang|vi|trung học phổ thông}}, 'high school'), ''CLB'' ({{lang|vi|câu lạc bộ}}, 'club'), ''CSDL'' ({{lang|vi|cơ sở dữ liệu}}, 'database'), ''NXB'' ({{lang|vi|nhà xuất bản}}, 'publisher'), {{lang|vi|ÔBACE}} ({{lang|vi|ông bà anh chị em}}, a general form of address), and {{lang|vi|CTTĐVN}} ({{lang|vi|các Thánh tử đạo Việt Nam}}, '[[Vietnamese Martyrs]]'). Longer examples include ''CHXHCNVN'' ({{lang|vi|Cộng hòa Xã hội chủ nghĩa Việt Nam}}, 'Socialist Republic of Vietnam') and ''MTDTGPMNVN'' ({{lang|vi|Mặt trận Dân tộc Giải phóng miền Nam Việt Nam}}, '[[Viet Cong|Liberation Army of South Vietnam or the National Liberation Front of South Vietnam]]'). Long initialisms have become widespread in legal contexts in [[Vietnam]], for example ''TTLT-VKSNDTC-TANDTC''.<ref>{{cite web |title=Từ viết tắt |trans-title=Abbreviations |publisher=[[BBC Academy]] |access-date=September 4, 2017 |url= https://www.bbc.co.uk/academy/vietnamese/article/art20131007102738486 |language=vi |quote=Chưa kể cách viết này còn dễ bị cho là lười biếng hoặc tỏ ra quan trọng, vì đây là cách chép nguyên xi, máy móc các cụm từ viết tắt từ văn bản pháp quy của chính quyền, như TTLT-VKSNDTC-TANDTC, khá phổ biến ở Việt Nam hiện nay. |archive-url= https://web.archive.org/web/20171120141047/http://www.bbc.co.uk/academy/vietnamese/article/art20131007102738486 |archive-date=November 20, 2017 |url-status=dead}}</ref> It is also common for a writer to coin an ad hoc initialism for repeated use in an article.

Each letter in an initialism corresponds to one [[morpheme]], that is, one syllable. When the first letter of a syllable has a tone mark or other diacritic, the diacritic may be omitted from the initialism, for example {{lang|vi|ĐNA}} or {{lang|vi|ĐNÁ}} for {{lang|vi|Đông Nam Á}} ('Southeast Asia') and ''LMCA'' or {{lang|vi|LMCÂ}} for {{lang|vi|Liên minh châu Âu}} ('European Union'). The letter {{lang|vi|[[Ư]]}} is often replaced by ''W'' in initialisms to avoid confusion with ''U'', for example ''UBTWMTTQVN'' or {{lang|vi|UBTƯMTTQVN}} for {{lang|vi|Ủy ban Trung ương Mặt trận Tổ quốc Việt Nam}} ('Central Committee of the [[Vietnamese Fatherland Front]]').

Initialisms are purely a written convenience, being pronounced the same way as their expansions. As the [[Vietnamese alphabet#Letter names and pronunciation|names of many Vietnamese letters]] are disyllabic, it would be less convenient to pronounce an initialism by its individual letters. Acronyms pronounced as words are rare in Vietnamese, occurring when an acronym itself is borrowed from another language. Examples include {{lang|vi|SIĐA}} ({{IPA|vi|s̪i˧ ˀɗaː˧|pron}}), a respelling of the French acronym ''SIDA'' ('AIDS'); ''VOA'' ({{IPA|vi|vwaː˧|pron}}), a literal reading of the English initialism for '[[Voice of America]]'; and ''[[NASA]]'' ({{IPA|vi|naː˧ zaː˧|pron}}), borrowed directly from the English acronym.

As in [[#Chinese|Chinese]], many compound words can be shortened to the first syllable when forming a longer word. For example, the term {{lang|vi|[[Viet Cong|Việt Cộng]]}} is derived from the first syllables of {{lang|vi|Việt Nam}} ('Vietnam') and {{lang|vi|Cộng sản}} ('communist'). This mechanism is limited to [[Sino-Vietnamese vocabulary]]. Unlike with Chinese, such [[clipped compound]]s are considered to be [[portmanteau]] words or [[blend word]]s rather than acronyms or initialisms, because the [[Vietnamese alphabet]] still requires each component word to be written as more than one character.

===General grammatical considerations===
====Declension====
In languages where nouns are [[Declension|declined]], various methods are used. An example is [[Finnish language|Finnish]], where a colon is used to separate inflection from the letters:
*An acronym is pronounced as a word: [[NATO]] or Nato {{IPA|fi|ˈnɑto|}} – {{lang|fi|Natoon}} {{IPA|[ˈnɑtoːn]}} 'into Nato'; another example is {{lang|fi|Nasalta}} 'from [[NASA]]'
*An acronym is pronounced as letters: EU {{IPA|[ˈeːˌʔuː]}} – {{lang|fi|EU:hun}} {{IPA|[ˈeːˌʔuːhun]}} 'into [the] EU'
*An acronym is interpreted as words: EU {{IPA|[euroːpan unioni]}} – {{lang|fi|EU:iin}} {{IPA|[ˈeu̯roːpɑnˌunioniːn]}} 'into [the] EU'
The process above is similar to the way that hyphens are used for clarity in English when prefixes are added to acronyms: thus ''pre-NATO policy'' (rather than ''preNATO'').

====Lenition====
In languages such as [[Scottish Gaelic]] and Irish, where [[lenition]] (initial consonant mutation) is commonplace, acronyms must also be modified in situations where case and context dictate it. In the case of Scottish Gaelic, a lower-case ''h'' is often added after the initial consonant; for example, '[[BBC Scotland]]' in the genitive case would be written as {{lang|gd|BhBC Alba}}, with the acronym pronounced ''VBC''. Likewise, the Gaelic acronym for {{lang|gd|telebhisean}} 'television' is {{lang|gd|TBh}}, pronounced ''TV'', as in English.

==See also==
* {{annotated link|Acrostic}}
* {{annotated link|Amalgamation (names)}}
* {{annotated link|Initialized sign}}
* {{annotated link|One-letter word}}
* {{annotated link|Syllabic abbreviation}}

== Explanatory notes ==
{{Notelist}}

==References==
{{reflist|40em}}

==External links==
{{Wiktionary|acronym|initialism|alphabetism}}

{{Personal names}}
{{Authority control}}

[[Category:Abbreviations]]
[[Category:Acronyms| ]]
[[Category:Types of words]]