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{{Short description|Typographic character indicating a question (?)}}
{{For-multi|the inverted question mark|¿|the backwards or mirrored question mark ⸮ used to indicate rhetorical questions (or sometimes irony or sarcasm)|Percontation point|the similar but dotless mark ʔ used in IPA|Glottal stop|other uses}}
{{Infobox punctuation
|mark        = ?
|name        = Question mark
|other_names =query, eroteme, interrogation point
|unicode     = {{unichar|003F|QUESTION MARK}}
|see_also    = [[Inverted question mark]]
}}
The '''question mark''' '''{{char|?}}''' (also known as '''interrogation point''', '''query''', or '''eroteme''' in [[journalism]]{{sfn|Truss|2003|page=139}}) is a [[punctuation|punctuation mark]] that indicates a [[question]] or [[interrogative clause]] or phrase in many [[language]]s.

==History==
The history of the question mark is contested. One popular theory posits that the shape of the symbol is inspired by the crook in a cat's tail, often attributed to the ancient Egyptians.<ref name=burb>{{cite news |last1=Casagrande |first1=June |title=A Word, Please: Curious cases surrounding the question mark |url=https://www.latimes.com/socal/burbank-leader/opinion/tn-blr-me-aword-20190109-story.html |access-date=15 May 2025 |work=Burbank Leader |publisher=Los Angeles Times |date=10 January 2019}}</ref> However, [[Egyptian hieroglyphics]] did not use punctuation marks.<ref>{{cite web |title=Daily Life in Ancient Egypt |url=http://giza.fas.harvard.edu/lessons/ancient-egyptian-writing |website=Digital Giza |publisher=The Giza Project at Harvard University |access-date=15 May 2025}}</ref> 

In the fifth century, [[Classical Syriac|Syriac]] Bible manuscripts used question markers, according to a 2011 theory by manuscript specialist Chip Coakley: he believes the ''zagwa elaya'' ("upper pair"), a vertical double dot over a word at the start of a sentence, indicates that the sentence is a question.<ref>{{cite web |title=The riddle of the Syriac double dot: it's the world's earliest question mark |url=https://www.cam.ac.uk/research/news/the-riddle-of-the-syriac-double-dot-its-the-worlds-earliest-question-mark |website=University of Cambridge |date=2011-07-21 |access-date=2022-11-01 |archive-date=2022-11-01 |archive-url=https://web.archive.org/web/20221101174509/https://www.cam.ac.uk/research/news/the-riddle-of-the-syriac-double-dot-its-the-worlds-earliest-question-mark |url-status=live}}</ref><ref>{{cite web |title=Symbol in Syriac may be world's first question mark |url=https://www.reuters.com/article/us-academic-questionmark-idUKTRE76K4ZI20110721 |website=Reuters |date=2011-07-21 |access-date=2022-11-01 |archive-date=2022-11-01 |archive-url=https://web.archive.org/web/20221101182412/https://www.reuters.com/article/us-academic-questionmark-idUKTRE76K4ZI20110721 |url-status=live}}</ref>

[[File:Btv1b6000718s.png|thumb|8th century ''punctus interrogativus'' from the [[Godescalc Evangelistary]]. ([https://gallica.bnf.fr/ark:/12148/btv1b6000718s/f12 BnF NAL 1203, f. 6v].)]]
From around 783, in [[Godescalc Evangelistary]], a mark described as "a lightning flash, striking from right to left" is attested.{{r|grammarphobia}}{{sfn|Truss |2003|page=159}} This mark is later called a {{wikt-lang|en|punctus interrogativus}}. According to some [[palaeography|paleographers]], it may have indicated [[intonation (linguistics)|intonation]], perhaps associated with early musical notation like [[neume]]s.<ref name=grammarphobia>{{cite web |title=The Grammarphobia Blog: Who invented the question mark? |url=https://www.grammarphobia.com/blog/2022/02/question-mark.html |website=www.grammarphobia.com |date=2022-02-28 |access-date=2022-11-01 |archive-date=2022-11-01 |archive-url=https://web.archive.org/web/20221101193645/https://www.grammarphobia.com/blog/2022/02/question-mark.html |url-status=live}}</ref> Another theory, is that the "lightning flash" was originally a [[tilde]] or [[titlo]], as in {{char|·~}}, one of many wavy or more or less slanted marks used in [[medieval]] texts for denoting things such as [[abbreviations]], which would later become various [[diacritics]] or [[Typographic ligature|ligatures]].<ref>{{cite book |first=M. B. |last=Parkes |title=Pause and Effect: An Introduction to the History of Punctuation in the West |publisher=[[University of California Press]] |date=1993 |isbn=0-520-07941-8}}</ref><ref>[http://www.straightdope.com/mailbag/mquestionmark.htm The Straight Dope on the question mark] {{webarchive |url=https://web.archive.org/web/20070711051031/http://www.straightdope.com/mailbag/mquestionmark.htm |date=July 11, 2007}} (link down)</ref> The creation of the ''punctus interrogativus'' has also been attributed to [[Alcuin of York]], an advisor to [[Charlemagne]].<ref name=burb/>

[[File:Punctus interrogativus from Bern, Bürgerbibliothek Cod. 162, f. 15r.jpg|thumb|An 11th century ''punctus interrogativus''; in the third line, before "tamen". ([[Burgerbibliothek of Berne|Burgerbibliothek Bern]], [https://www.e-codices.ch/en/bbb/0162/15r Cod. 162, f. 15r].)]]
From the 10th century, the pitch-defining element (if it ever existed) seems to have been gradually forgotten, so that the "lightning flash" sign (with the stroke sometimes slightly curved) is often seen indifferently at the end of clauses, whether they embody a question or not.{{citation needed|date=November 2022}}

In the early 13th century, when the growth of communities of scholars ([[university|universities]]) in Paris and other major cities led to an expansion and streamlining of the book-production trade,<ref>De Hamel, Christopher ''History of Illuminated Manuscripts'', 1997</ref> punctuation was rationalized by assigning the "lightning flash" specifically to [[interrogative]]s; by this time, the stroke was more sharply curved and can easily be recognized as the modern question mark (see, for example, ''{{interlanguage link|De Aetna|it}}'' (1496) printed by [[Aldus Manutius|Aldo Manuzio]] in [[Venice]]<ref>{{cite book|last=Bembo|first=Pietro|author-link=Pietro Bembo|date=1495–1496|title=De Aetna|url=https://digital.wlb-stuttgart.de/index.php?id=6&tx_dlf%5Bid%5D=1582&tx_dlf%5Bpage%5D=14|location=[[Venice]]|publisher=[[Aldus Manutius|Aldo Pio Manuzio]]|at=f. 4v}}</ref>).

In 1598, the English term ''point of interrogation'' is attested in an [[Italian language|Italian]]–English dictionary by [[John Florio]].<ref>{{cite book |last=Florio |first=John |author-link=John Florio |title=A worlde of wordes, or, Most copious, and exact dictionarie in Italian and English |date=1598 |publisher=By Arnold Hatfield for Edw. Blount |location=London |page=[https://archive.org/details/worldeofwordesor00flor/page/188 188] |url=https://archive.org/details/worldeofwordesor00flor/page/188|quote=Iterogatiuo punto, a point of interrogation.}}</ref>

In the 1850s, the term ''question mark'' is attested:<ref>{{cite book |last1=Parker |first1=Richard Green |last2=Watson |first2=J. Madison |title=The National Second Reader: Containing preliminary exercises in articulation, pronunciation, and punctuation |series=National series; no. 2 |date=1859 |publisher=A. S. Barnes & Burr |location=New York |page=[https://hdl.handle.net/2027/nc01.ark:/13960/t26988j57?urlappend=%3Bseq=20 20] |hdl=2027/nc01.ark:/13960/t26988j57 |url=https://hdl.handle.net/2027/nc01.ark:/13960/t26988j57}}</ref>

{{blockquote|1=The mark which you are to notice in this lesson is of this shape '''?''' You see it is made by placing a little crooked mark over a period.... The name of this mark is the ''Question Mark'', because it is always put after a question. Sometimes it is called by a longer and harder name. The long and hard name is the ''Interrogation Point''.}}

==Scope==
In English, the question mark typically occurs at the end of a sentence, where it replaces the [[full stop]] (period).  However, the question mark may also occur at the end of a clause or phrase, where it replaces the comma {{crossreference|(see also [[Question comma]])}}:

:"Is it good in form? style? meaning?"
or:
:"Showing off for him, for all of them, not out of hubris—hubris? him? what did he have to be hubrid about?—but from mood and nervousness."
:— [[Stanley Elkin]].<ref>{{cite book |first=Stanley |last=Elkin |author-link=Stanley Elkin |title=The MacGuffin |date=1991 |page=173}}</ref>

This is quite common in [[Spanish (language)|Spanish]], where the use of bracketing question marks explicitly indicates the scope of interrogation.

:{{lang|es|En el caso de que no puedas ir con ellos, ¿quieres ir con nosotros?}} ('In case you cannot go with them, would you like to go with us?')

A question mark may also appear immediately after questionable data, such as dates:
:''Genghis Khan (1162?–1227)''

==In other languages and scripts==
===Opening and closing question marks in Spanish===
{{Main|Inverted question and exclamation marks}}
[[File:Question opening-closing.svg|thumb|upright=0.6|class=skin-invert-image|Opening and closing question marks]]
In Spanish, since the second edition of the {{lang|es|Ortografía}} of the {{lang|es|[[Real Academia Española]]|italic=unset}} in 1754, interrogatives require both opening {{char|¿}} and closing {{char|?}} question marks.{{sfn|Truss|2003|page=142–143}}<ref>{{cite book |publisher=[[Real Academia Española]] |location=Madrid |title=Ortografía de la Lengua Castellana |language=es |url= https://archive.org/details/ortografiadelale00acaduoft |date=1779 |orig-date=1754 |via=[[Internet Archive]]}}</ref> An interrogative sentence, clause, or phrase begins with an [[Inverted question mark and exclamation point|inverted question mark]] {{char|¿}} and ends with the question mark {{char|?}}, as in:
:{{lang|es|Ella me pregunta «¿qué hora es?»}} – 'She asks me, "What time is it?{{"'}}
Question marks must always be matched, but to mark uncertainty rather than actual interrogation omitting the opening one is allowed, although discouraged:<ref>[http://lema.rae.es/dpd/srv/search?key=interrogación#3d Interrogación y exclamación (signos de). Punto 3d.]</ref>
:{{lang|es|Gengis Khan (¿1162?–1227)}} is preferred in Spanish over {{lang|es|Gengis Khan (1162?–1227)}}
The omission of the opening mark is common in informal writing, but is considered an error.  The one exception is when the question mark is matched with an exclamation mark, as in:
:{{lang|es|¡Quién te has creído que eres?}} – 'Who do you think you are?!'
(The order may also be reversed, opening with a question mark and closing with an exclamation mark.) Nonetheless, even here the {{lang|es|Academia|italic=unset}} recommends matching punctuation:<ref>[http://lema.rae.es/dpd/srv/search?key=interrogación#3b Interrogación y exclamación (signos de). Punto 3b.]</ref>
:{{lang|es|¡¿Quién te has creído que eres?!}}
The opening question mark in Unicode is {{unichar|00BF|INVERTED QUESTION MARK|html=}}.

===Solomon Islands Pidgin===
In [[Solomon Islands Pidgin]], the question can be between question marks since, in yes/no questions, the intonation can be the only difference.

{{lang|pis|?Solomon Aelan hemi barava gudfala kandre, ia man?}} ('[[Solomon Islands]] is a great country, isn't it?')<ref name="Lee">{{cite book |last=Lee |first=Ernie |title=Pidgin Phrasebook |date=1999 |publisher=Lonely Planet Publications |location=Hawthorn, Victoria, Australia |isbn=0864425872 |pages=63–64 |edition=2nd}}</ref>

===Armenian question mark===
[[File:Harcakan.svg|thumb|upright=0.5|class=skin-invert-image|Armenian question mark]]
In [[Armenian alphabet|Armenian]], the question mark is a [[diacritic]] that takes the form of an open circle and is placed over the stressed vowel of the question word. It is defined in Unicode at {{unichar|055E|ARMENIAN QUESTION MARK|cwith=◌}}.
{{anchor|Erotimatiko}}
{{Clear left}}

===Greek question mark===
The [[Greek language|Greek]] question mark ({{langx|el|ερωτηματικό|links=no|translit=erōtīmatikó}}) looks like {{char|;}}. It appeared around the same time as the Latin one, in the 8th century.<ref>{{cite book |last=Thompson |first=Edward Maunde |url=https://archive.org/details/greeklatin00thomuoft |via=[[Internet Archive]] |title=An Introduction to Greek and Latin Palaiography |pages=[https://archive.org/details/greeklatin00thomuoft/page/60 60] ff |publisher=Clarendon Press |location=Oxford |date=1912 |access-date=December 10, 2017}}</ref> It was adopted by [[Church Slavonic]] and eventually settled on a form essentially similar to the Latin [[semicolon]]. In [[Unicode]], it is separately encoded as {{unichar|037E|GREEK QUESTION MARK}}, but the similarity is so great that the [[code point]] is [[Unicode normalisation|normalised]] to {{unichar|003B|SEMICOLON}}, making the marks identical in practice.<ref>{{cite web |last=Nicolas |first=Nick |work=[[Thesaurus Linguae Graecae]]: A Digital Library of Greek Literature |publisher=University of California, Irvine |url=http://www.tlg.uci.edu/~opoudjis/unicode/punctuation.html |title=Greek Unicode Issues: Punctuation |url-status=dead |archive-url=https://web.archive.org/web/20150118083005/http://www.tlg.uci.edu/~opoudjis/unicode/punctuation.html |archive-date=January 18, 2015 |date=November 20, 2014}}". 2005. Accessed 7 October 2014.</ref>

===Mirrored question mark in right-to-left scripts===
{{redirect|؟|the symbol this may also stand for|Irony punctuation}}
[[File:Arabic Question mark (RTL).svg|upright=0.5|thumb|left|class=skin-invert-image|Mirrored question mark in [[Arabic alphabet|Arabic]] and [[Persian alphabet|Perso-Arabic]]]]

In [[Arabic]] and other languages that use Arabic script such as [[Persian language|Persian]], [[Urdu]] and [[Uyghur language|Uyghur (Arabic form)]], which are written from [[Right-to-left script|right to left]], the question mark is mirrored right-to-left from the Latin question mark. In Unicode, two encodings are available: {{Unicode character|061F|ARABIC QUESTION MARK|html=|note=with [[Bi-directional text|bi-directional]] code AL: Right-to-Left Arabic}} and {{unichar|2E2E|REVERSED QUESTION MARK|html=|note=with bi-directional code Other Neutrals}}. Some browsers may display the character in the previous sentence as a forward question mark due to font or text directionality issues.

The Arabic question mark is also used in some other right-to-left scripts: [[Maldivian language|Dhivehi]],<ref>{{Cite web |title=Dhivehi orthography & Thaana orthography summary |url=https://r12a.github.io/scripts/thaa/dv.html |access-date=2025-02-07 |website=r12a.github.io}}</ref> [[N'Ko script|N'Ko]],<ref>{{Cite web |title=N’Ko orthography notes |url=https://r12a.github.io/scripts/nkoo/nqo.html |access-date=2025-02-07 |website=r12a.github.io}}</ref> [[Syriac alphabet|Syriac]],<ref>{{Cite web |title=Assyrian orthographic notes |url=https://r12a.github.io/scripts/syrc/aii.html |access-date=2025-02-07 |website=r12a.github.io}}</ref> and [[Adlam script|Adlam]].<ref name="r12a">{{cite web |date=5 January 2023 |title=Adlam/Pular orthography notes |url=https://r12a.github.io/scripts/adlm/fuf.html#inline |url-status=live |archive-url=https://web.archive.org/web/20230116104616/https://r12a.github.io/scripts/adlm/fuf.html#inline |archive-date=16 January 2023 |access-date=16 January 2023 |website=r12a.github.io}}</ref> Adlam also has {{unichar|1e95f|Adlam initial question mark|use=yes|use2=ff}}: {{lang|ff-Adlm|𞥟 𞤢𞤤𞤢𞥄 ؟}}, 'No?'.<ref name="r12a" />

[[Hebrew alphabet|Hebrew script]] is also written right-to-left, but it uses a question mark that appears on the page in the same orientation as the left-to-right question mark (e.g. {{lang|he|את מדברת עברית?}}).{{sfn|Truss|2003|page=143}}
{{Clear left}}

===Fullwidth question mark in East Asian languages===
The question mark is also used in modern writing in [[Chinese language|Chinese]] and, to a lesser extent, [[Japanese language|Japanese]]. Usually, it is written as [[fullwidth form]] in Chinese and Japanese, in Unicode: {{unichar|ff1f|FULLWIDTH QUESTION MARK|ulink=|html=}}. Fullwidth form is always preferred in official usage.<ref>{{cite web |title=标点符号用法 |url=http://www.moe.gov.cn/ewebeditor/uploadfile/2015/01/13/20150113091548267.pdf |website=Chinese Ministry of Education |lang=zh-hans |quote=句号、逗号、顿号、分号、冒号均置于相应文字之后，占一个字位置，居左下，不出现在一行之首。 }}</ref><ref>{{cite web |title=常用格式說明 |url=http://www.cjpsy.com/_i/assets/upload/files/(%E5%85%AC%E5%91%8A%E7%89%88)%E4%B8%AD%E8%8F%AF%E5%BF%83%E7%90%86%E5%AD%B8%E5%88%8A%E5%B8%B8%E7%94%A8%E6%A0%BC%E5%BC%8F%E8%AA%AA%E6%98%8Ev6.pdf |website=Chinese Journal of Psychology |lang=zh-hant |quote=請使用新式標準符號，所有的中文標點符號都要佔全形。}}</ref><ref>{{cite web |title=記述上の約束事 |url=https://jss-sociology.org/bulletin/guide/promise |website=The Japan Sociological Society |date=8 February 2019 |lang=ja |quote=和文を書くときには，原則としてすべて全角文字を使用しなければならない．漢字，ひらがな，カタカナのみならず，句読点やカッコ記号なども，全角文字を使用すること（このルールの例外については，そのつど述べる）．}}</ref> In [[Korean language|Korean]], however, halfwidth is used.<ref>{{cite journal | title=한글 타이포그라피 환경으로서의 문장부호에 대하여 : 표준화 이슈를 중심으로 개선 방향 제안 |author=심우진 | journal=글짜씨 |date=December 2011 | volume=3 | issue=2 | issn=2093-1166 | pages=987–1005 | url=https://www.dbpia.co.kr/journal/articleDetail?nodeId=NODE07406554 | language=ko | access-date=2024-10-07 |quote=일반적인 키보드 입력 환경에서 사용하는 문장 부호는 대부분 반각 문장 부호이며, 이들은 라틴 문자의 문장 부호를 차용한 것이다. }}</ref>

Japanese has an interrogative particle, [[wiktionary:か|か]] (ka), which functions grammatically like a question mark. Therefore, the question mark is not historically used Japanese, and still not officially sanctioned for use in government publications or school textbooks, but its popularity has been gradually increasing among younger people. Where official usage is {{lang|ja|終わったのかもしれませんよ。}}, some people would now informally write {{lang|ja|終わったのかもしれませんよ？}} to express "It may be over"; the question mark here adds a nuance of uncertainty to the sentence rather than turning it into a question.<ref>{{cite web |title=疑問文でないのに"？"を付けてもよいか？ |author=塩田雄大 |url=https://www.nhk.or.jp/bunken/research/kotoba/20170401_4.html |website=NHK放送文化研究所 |lang=ja }}</ref>

Chinese also has a spoken indicator of questions, which is [[wiktionary:吗|吗]] (ma). However, the question mark should always be used after {{lang|zh|吗}} when asking questions.<ref>{{cite web |title=标点符号用法 |url=http://www.moe.gov.cn/ewebeditor/uploadfile/2015/01/13/20150113091548267.pdf |website=Chinese Ministry of Education |lang=zh-hans |quote=使用问号主要根据语段前后有较大停顿、带有疑问语气和语调，并不取决于句子的长短。}}</ref>

===In other scripts===
Some other scripts have a specific question mark:
* {{unichar|1367|ETHIOPIC QUESTION MARK|nlink=Ge'ez writing system}}
* {{unichar|A60F|VAI QUESTION MARK|nlink=Vai script}} 
* {{unichar|2CFA|COPTIC OLD NUBIAN DIRECT QUESTION MARK|nlink=Old Nubian language}}, and {{unichar|2CFB|COPTIC OLD NUBIAN INDIRECT QUESTION MARK}}
* {{unichar|1945|LIMBU QUESTION MARK}}

==Stylistic variants==
[[French orthography]] specifies a [[narrow non-breaking space]] before the question mark.<ref>{{cite book |title=Lexique des règles typographiques en usage à l'Imprimerie nationale |language=fr |publisher=[[Imprimerie nationale]] |isbn=978-2-7433-0482-9 |edition=3e |date=October 2007 |chapter= Ponctuation |pages=148–149}}.</ref> (e.g., "{{lang|fr|Que voulez-vous boire{{nnbsp}}?}}"); in [[English orthography]], no space appears in front of the question mark (e.g. "What would you like to drink?").<ref>{{Cite web |title=Learn English Punctuation - English Punctuation Rules |url=https://www.learnenglish.de/punctuation/punctuationtext.html#:~:text=Question%20marks%20go%20at%20the,(two%20spaces%20for%20purists). |access-date=2024-02-20 |website=www.learnenglish.de}}</ref>

==Typological variants of ''?''==
The rhetorical question mark or percontation point (see [[Irony punctuation]]) was invented by [[Henry Denham]] in the 1580s and was used at the end of a [[rhetorical question]];{{sfn|Truss|2003|page=142}}  however, it became obsolete in the 17th century.  It was the reverse of an ordinary question mark, so that instead of the main opening pointing back into the sentence, it opened away from it.{{sfn|Truss|2003|page=142}} This character can be represented using {{unichar|2E2E|nlink=Irony punctuation#Irony mark}}.

Bracketed question marks can be used for rhetorical questions, for example {{char|Oh, really(?)}}, in informal contexts such as [[closed captioning]].

The question mark can also be used as a [[Meta (prefix)|meta]]-sign to signal uncertainty regarding what precedes it. It is usually put between brackets: {{char|(?)}}. The uncertainty may concern either a superficial level (such as unsure spelling), or a deeper [[Truth-conditional semantics|truth]] (real [[Meaning (philosophy of language)|meaning]]).

In typography, some other variants and combinations are available: "⁇," "⁈," and "⁉," are usually used for [[chess annotation symbols]]; the [[interrobang]], "‽," is used to combine the functions of the question mark<ref name="A course of reading for common schools and the lower classes of academies">{{cite book |url=https://books.google.com/books?id=4t4NAQAAMAAJ&q=%22interrogative+point%22&pg=PA44 |title=A Course of Reading for Common Schools and the Lower Classes of Academies |date=1851 |access-date=November 22, 2013 |last=Mandeville |first=Henry}}</ref> and the [[exclamation mark]], superposing these two marks.

Unicode makes available these variants:
* {{unichar|2047|Double Question Mark|html=}}
* {{unichar|2048|Question Exclamation Mark|html=}}
* {{unichar|2049|Exclamation Question Mark|html=}}
** {{Emoji presentation|⁉}} with an [[emoji variation selector]]
* {{unichar|203D|Interrobang|nlink=Interrobang|html=}}
* {{unichar|2E18|Inverted Interrobang|nlink=Inverted_question_and_exclamation_marks|html=}}
* {{unichar|2E2E|Reversed Question Mark|nlink=Irony_punctuation|html=}}
* {{unichar|061F|Arabic Question Mark|html=}}
* {{unichar|FE56|Small Question Mark|html=}}
* {{unichar|00BF|Inverted Question Mark|nlink=Inverted_question_and_exclamation_marks|html=}}
* {{unichar|2753|Black Question Mark Ornament}}
* {{unichar|2754|White Question Mark Ornament}}
* {{unichar|1f679|heavy interrobang ornament}}
* {{unichar|1f67A|sans-serif interrobang ornament}}
* {{unichar|1f67b|heavy sans-serif interrobang ornament}}

==Computing==
{{More citations|section|date=September 2025}}
In [[computing]], the question mark [[Character (computing)|character]] is represented by [[ASCII]] code 63 (0x3F hexadecimal), and is located at Unicode code-point {{unichar|003F|QUESTION MARK|html=}}. The full-width (double-byte) equivalent ('''？'''), is located at code-point {{unichar|FF1F|FULLWIDTH QUESTION MARK|html=}}.<ref>{{cite web |title=Character Codes – HTML Codes, Hexadecimal Codes & HTML Names |url=http://www.character-code.com/ |work=Character-Code.com |access-date=August 7, 2016 |archive-date=August 7, 2016 |archive-url=https://web.archive.org/web/20160807130637/http://www.character-code.com/ |url-status=live}}</ref>

The [[Inverted question mark and exclamation point|inverted question mark]] ('''¿''') corresponds to Unicode code-point {{unichar|00BF|INVERTED QUESTION MARK|html=}}

In shell and scripting languages, the question mark is often utilized as a [[wildcard character]]: a symbol that can be used to substitute for any other character or characters in a [[String (computer science)|string]]. In particular, [[glob (programming)|filename globbing]] uses "?" as a substitute for any one character, as opposed to the [[asterisk]], "*", which matches zero or more characters in a string.

The question mark is used in ASCII renderings of the [[International Phonetic Alphabet]], such as [[SAMPA]], in place of the [[glottal stop]] symbol, {{IPA|'''ʔ'''}}, (which resembles "'''?'''" without the dot), and corresponds to Unicode code point {{unichar|0294|LATIN LETTER GLOTTAL STOP|html=}}.

In [[computer programming]], the symbol "'''?'''" has a special meaning in many [[programming language]]s. 
* In [[C (programming language)|C]]-descended languages, <code>?</code> is part of the [[?:|<code>?:</code>]] operator, which is used to evaluate simple [[Boolean domain|boolean conditions]]. 
* In [[C Sharp (programming language)|C#]] 2.0, the <code>?</code> modifier is used to handle [[Nullable type|nullable data types]] and <code>??</code> is the [[null coalescing operator]]. 
* In [[Java (programming language)|Java]], <code>?</code> can represent a [[Wildcard (Java)|wildcard]] type parameter. For instance, <code>List<?></code> denotes a list that can hold any type (but not [[null pointer|{{mono|null}}]]), and <code>List<? '''extends''' T></code> and <code>List<? '''super''' T></code> denote a list that can hold any type that inherits from/is an ancestor class of (respectively) type <code>T</code> (including <code>T</code> itself).
* In the [[POSIX]] syntax for [[regular expression]]s, such as that used in [[Perl]] and [[Python (programming language)|Python]], <code>?</code> stands for "zero or one instance of the previous subexpression", i.e. an optional element. It can also make a quantifier like <code>{x,y}</code>, <code>+</code> or <code>*</code> match as few characters as possible, making it lazy, e.g. <code lang="js">/^.*?px/</code> will match the substring <code>165px</code> in <code>165px 17px</code> instead of matching <code>165px 17px</code>.{{efn|The [[Perl Compatible Regular Expressions]] library implements the <code>U</code> flag, which reverses behavior of quantifiers: these become lazy by default, and <code>?</code> can make them greedy.|name="pcre-qm-Uflag"}} 
* In certain implementations of the [[BASIC]] programming language, the <code>?</code> character may be used as a shorthand for the "print" function; in others (notably the [[BBC BASIC]] family), <code>?</code> is used to address a single-byte memory location. 
* In [[OCaml]], the question mark precedes the label for an optional parameter. 
* In [[Scheme (programming language)|Scheme]], as a convention, symbol names ending in <code>?</code> are used for predicates, such as <code>odd?</code>, <code>null?</code>, and <code>eq?</code>. Similarly, in [[Ruby (programming language)|Ruby]], method names ending in <code>?</code> are used for predicates. 
* In [[Swift (programming language)|Swift]] a type followed by <code>?</code> denotes an [[option type]]; <code>?</code> is also used in "optional chaining", where if an option value is nil, it ignores the following operations. Similarly, in [[Kotlin (programming language)|Kotlin]], a type followed by <code>?</code> is [[Nullable type|nullable]] and functions similar to option chaining are supported. 
* In [[APL (programming language)|APL]], <code>?</code> generates random numbers or a random subset of indices. 
* In [[Rust (programming language)|Rust]], a <code>?</code> suffix on a function or method call indicates error handling. 
* In [[SPARQL]], the question mark is used to introduce variable names, such as <code>?name</code>. In [[MUMPS]], it is the pattern match operator.
* In the [[Xbase]] family of programming languages, which includes [[dBase]] and [[FoxPro]], either one or two question marks at the start of a line of code serve as a shorthand for the Print function. The effect is to evaluate the following expression(s) and to send the result(s) either to the screen or a printer. A single question mark sends a carriage return and line feed before the output; this is not the case with a double question mark.<ref>{{cite web |title=The Xbase++ Reference Documentation |url=https://doc.alaska-software.com/ |website=Alaska Software |access-date=23 March 2025}}</ref><ref>{{cite web |title=Visual FoxPro Reference |url=https://hackfox.github.io/section4/ |website=Hacker’s Guide to Visual FoxPro |publisher=Hentzenwerke Publishing |access-date=23 March 2025}}</ref>

In many [[Web browser]]s and other computer programs, when converting text between encodings, it may not be possible to map some characters into the target [[character set]]. In this situation it is common to replace each unmappable character with a question mark <samp>?</samp>, inverted question mark <samp>¿</samp>, or the Unicode [[replacement character]], usually rendered as a white question mark in a black diamond: {{unichar|FFFD|REPLACEMENT CHARACTER}}. This commonly occurs for apostrophes and quotation marks when they are written with software that uses its own proprietary non-standard code for these characters, such as [[Microsoft Office]]'s [[Quotation marks in English#Smart quotes|"smart quotes"]].

The generic [[Uniform Resource Locator|URL]] syntax allows for a [[query string]] to be appended to a resource location in a Web address so that additional information can be passed to a script; the query mark, <code>?</code>, is used to indicate the start of a query string. A query string is usually made up of a number of different field/value pairs, each separated by the [[ampersand]] symbol, <code>&</code>, as seen in this URL:

<code><nowiki>http://www.example.com/search.php?query=testing&database=English</nowiki></code>

Here, a script on the page <samp>search.php</samp> on the server <samp>www.example.com</samp> is to provide a response to the query string containing the pairs <samp>query=</samp><kbd>testing</kbd> and <samp>database=</samp><kbd>English</kbd>.

==Games==
In [[algebraic chess notation]], some [[chess punctuation]] conventions include: "'''?'''" denotes a bad move, "'''??'''" a [[blunder (chess)|blunder]], "'''?!'''" a [[dubious]] move, and "'''!?'''" an interesting move.

In [[Scrabble]], a question mark indicates a blank tile.<ref>{{cite web |url=http://www.tucsonscrabble.com/articles/glossary.html |title=Scrabble Glossary |publisher=Tucson Scrabble Club |access-date=February 6, 2012 |archive-date=August 30, 2011 |archive-url=https://web.archive.org/web/20110830073348/http://www.tucsonscrabble.com/articles/glossary.html |url-status=dead}}</ref>

==Linguistics==
In most areas of [[linguistics]], but especially in [[syntax]], a question mark in front of a word, phrase or sentence indicates that the form in question is strongly dispreferred, "questionable" or "strange", but not outright [[ungrammatical]].{{efn|One article notes succinctly that "common practice in linguistics [is that] an asterisk preceding a word, a clause or a sentence is used to indicate ungrammaticality or unacceptability, while a question mark is used to indicate questionable usage",<ref name="Xu"/>{{rp|15}} another that, "A question mark indicates that the example is marginal; an asterisk indicates unacceptability"<ref name="Simons"/>{{rp|409}} and another that "examples preceded by an asterisk are ungrammatical, and those preceded by a question mark would be considered strange".<ref name="Everett"/>{{rp|623}}}}  (The [[asterisks in linguistics|asterisk]] is used to indicate outright ungrammaticality.<ref name="Graffi"/>{{rp|332}})

Other sources go further and use several symbols (e.g. the question mark and the asterisk plus {{code|?*}} or the [[degree symbol]] {{code|°}}) to indicate gradations or a continuum of acceptability.{{efn|One example is "rough approximations of acceptability are given in four gradations and indicated as follows: normal and preferred, no mark; acceptable but not preferred, degree sign {{code|°}}; marginally acceptable, question mark ({{code|?}}); unacceptable, asterisk ({{code|*}})."<ref name="Timberlake"/>{{rp|123–24}}}}

Yet others use double question marks {{code|??}} to indicate a degree of strangeness between those indicated by a single question mark and that indicated by the combination of question mark and asterisk.<ref>{{Cite book |first=R. L. |last=Trask |author-link=Larry Trask |title=A Dictionary of Grammatical Terms in Linguistics |location=London |publisher=Routledge |date=1993 |isbn=0-415-08627-2 |page=227}}</ref><ref>{{Cite book |first=Michael Alan |last=Jones |title=Foundations of French Syntax |series=Cambridge Textbooks in Linguistics |location=Cambridge |publisher=Cambridge University Press |date=1996 |isbn=0-521-38104-5 |page=xxv}}</ref>

== Mathematics and formal logic==
{{anchor|Mathematics|reason=Original section name.}}
In [[mathematics]], "'''?'''" commonly denotes [[Minkowski's question mark function]].

In [[linear logic]], the question mark denotes one of the exponential modalities that control weakening and contraction.

When placed above the relational symbol in an [[equation]] or [[inequality (mathematics)|inequality]], a question-mark annotation means that the stated relation is "questioned". This can be used to ask whether the relation might be true or to point out the relation's possible invalidity.

*{{unichar|225F|QUESTIONED EQUAL TO}}
*{{unichar|2A7B|LESS-THAN WITH QUESTION MARK ABOVE}}
*{{unichar|2A7C|GREATER-THAN WITH QUESTION MARK ABOVE}}

==Medicine==
A question mark is used in English medical notes to suggest a possible [[diagnosis]]. It facilitates the recording of a doctor's impressions regarding a patient's symptoms and signs. For example, for a patient presenting with left [[lower abdominal pain]], a differential diagnosis might include ''?[[diverticulitis]]'' (read as "query diverticulitis").

==See also==
{{div col|colwidth=30em}}
* {{annotated link|Betteridge's law of headlines}}
* [[HH 46/47#History of observations|Cosmic "Question Mark"]]
* {{annotated link|High rising terminal}} ('upspeak', 'uptalk')
* {{annotated link|Inquiry}}
* {{annotated link|Interrobang}}
* {{annotated link|Irony punctuation}}
* [[List of typographical symbols and punctuation marks]]
* {{annotated link|Terminal punctuation}}
* [[Unicode input#.notdef.|.notdef. symbol]]{{snd}} diamond with a question mark, �, or a box with a question mark in it, ⍰, used to indicate that a font lacks the desired character.
{{div col end}}

==Notes==
{{notelist}}

==References==
{{reflist|refs=
<ref name="Everett">{{cite journal |last1=Everett |first1=Daniel L. |date=August–October 2005 |title=Cultural Constraints on Grammar and Cognition in Pirahã: Another Look at the Design Features of Human Language |url=https://www.jstor.org/stable/10.1086/431525 |journal=Current Anthropology |volume=46 |issue=4 |pages=621–646 |doi=10.1086/431525 |jstor=10.1086/431525 |s2cid=2223235 |access-date=5 September 2023|hdl=2066/41103 |hdl-access=free }}</ref>
<ref name="Graffi">{{cite journal |last=Graffi |first=Giorgio |date=May 2002 |title=The Asterisk from Historical to Descriptive and Theoretical Linguistics: An historical note. |url=https://www.jbe-platform.com/content/journals/10.1075/hl.29.3.04gra |journal=Historiographia Linguistica |volume=29 |issue=3 |pages=329–338 |doi=10.1075/hl.29.3.04gra |access-date=5 September 2023|url-access=subscription }}</ref>
<ref name="Simons">{{cite journal |last=Simons |first=Mandy |date=August 1996 |title=Pronouns and Definite Descriptions: A Critique of Wilson |url=https://www.jstor.org/stable/2941036 |journal=The Journal of Philosophy |volume=93 |issue=8 |pages=408–420 |doi=10.2307/2941036 |jstor=2941036 |access-date=5 September 2023}}</ref>
<ref name="Timberlake">{{cite journal |last=Timberlake |first=Alan |date=Summer 1975 |title=Hierarchies in the Genitive of Negation |url=https://www.jstor.org/stable/306765 |journal=The Slavic and East European Journal |volume=19 |issue=2 |pages=123–138 |doi=10.2307/306765 |jstor=306765 |access-date=5 September 2023|url-access=subscription }}</ref>
<ref name="Xu">{{cite journal |last=Xu |first=Hui Ling |date=2007 |title=Aspect of Chaozhou Grammar A Synchronic Description of the Jieyang Variety / 潮州話揭陽方言語法研究  |url=https://www.jstor.org/stable/23826160 |journal=Journal of Chinese Linguistics Monograph Series |volume= |issue=22 |pages=i–xiv, 1–304 |jstor=23826160 |issn=2409-2878 |access-date=5 September 2023}}</ref>
}}

===Bibliography===
{{Refbegin}}
*{{cite book |last=Truss |first=Lynne |title=[[Eats, Shoots & Leaves]]: The Zero Tolerance Approach to Punctuation |date=2003 |publisher=Profile Books |location=London |isbn=1861976127}}
*{{cite book |last1=Lupton |first1=Ellen |last2=Miller |first2=J. Abbott |chapter=Period Styles: A Punctuated History |title=The Norton Reader |edition=11th |editor-first=Linda H. |editor-last=Peterson |publisher=Norton |date=2003 |chapter-url= http://www.think-ng.com/design/ngjenniferbooklet/final.pdf |url-status=dead |archive-url= https://web.archive.org/web/20070614005756/http://www.think-ng.com/design/ngjenniferbooklet/final.pdf |archive-date=June 14, 2007 |access-date=December 10, 2017 |via=Think-gn.com – online excerpt (at least – may be full text of chapter), pp. 3–7}}
{{Refend}}

==External links==
{{Commons|Question mark}}
*{{cite web |url=http://grammar.ccc.commnet.edu/grammar/marks/question.htm |title=The Question Mark |work=Guide to Grammar & Writing |publisher=[[Capital Community College]] Foundation |location=Hartford, Connecticut |date=2004 |access-date=10 December 2017 |archive-date=8 September 2006 |archive-url=https://web.archive.org/web/20060908101340/http://grammar.ccc.commnet.edu/grammar/marks/question.htm |url-status=dead}} – provides an overview of question mark usage, and the differences between direct, indirect, and rhetorical questions.

{{navbox punctuation}}
{{Authority control}}

{{DEFAULTSORT:Question Mark}}
[[Category:Interrogative words and phrases]]
[[Category:Punctuation]]
[[Category:Typographical symbols]]