View source for Century

{{short description|Unit of time lasting 100 years}}
{{other uses}}
A '''century''' is a period of 100 [[year]]s or 10 [[decade]]s. Centuries are numbered [[names of numbers in English#Ordinal numbers|ordinally]] in English and many other languages. The word ''century'' comes from the [[Latin]] ''centum'', meaning ''one hundred''.  ''Century'' is sometimes abbreviated as '''c.'''<ref>{{Cite web|url = http://public.oed.com/how-to-use-the-oed/abbreviations/|title = Oxford English Dictionary – List of Abbreviations}}</ref>

A [[centennial]] or centenary is a hundredth anniversary, or a celebration of this, typically the remembrance of an event which took place a hundred years earlier.

== Start and end of centuries ==
Although a century can mean any arbitrary period of 100 [[years]], there are two viewpoints on the nature of standard centuries. One is based on strict construction, while the other is based on popular perception.  

According to the strict construction, the 1st century [[AD]], which began with [[AD 1]], ended with [[AD 100]], and the 2nd century with AD [[200]];{{NoteTag|[[AD]] and [[Common Era|CE]] year numbering, which are numerically equivalent, are now commonly used to number years, including those which occurred before these notations were invented; AD did not become widespread in Europe until early in the 2nd millennium.}} in this model, the ''n''-th century starts with a year that follows a year with a multiple of 100 (except the first century as it began after the year [[1 BC]]) and ends with the next coming year with a multiple of 100 (''100n''), i.e. the 20th century comprises the years '''1901''' to '''2000''', and the 21st century comprises the years '''2001''' to '''2100''' in strict usage.<ref>{{cite web |title=When Did the 21st Century Start? |url=https://www.timeanddate.com/counters/mil2000.html#:~:text=The%2021st%20Century%20Started%20in%202001&text=The%20year%20number%20in%20the,BC%2C%3A%20What's%20the%20difference%3F |website=timeanddate.com |access-date=23 November 2020}}</ref>

In common perception and practice, centuries are structured by grouping years based on sharing the 'hundreds' digit(s). In this model, the ''n''-th century starts with the year that ends in "00" and ends with the year ending in "99";<ref>{{Cite web| title = century | work = Oxford Dictionaries| access-date = 20 January 2021| url = https://www.lexico.com/definition/century| archive-url = https://web.archive.org/web/20191230065254/https://www.lexico.com/definition/century| url-status = dead| archive-date = December 30, 2019}}</ref> for example, in [[popular culture]], the years '''1900''' to '''1999''' constitute the 20th century, and the years '''2000''' to '''2099''' constitute the 21st century.<ref>{{Cite web| title = Centuries and How to Refer to Them | work = Merriam-Webster| access-date = 27 April 2021 | url = https://www.merriam-webster.com/words-at-play/centuries-and-how-to-refer-to-them}}</ref> (This is similar to the grouping of [[Decade#0-to-9 decade|"0-to-9 decades"]] which share the 'tens' digit.) 

To facilitate calendrical calculations by computer, the [[astronomical year numbering]] and [[ISO 8601]] systems both contain a [[year zero]], with the astronomical year 0 corresponding to the year 1 BC, the astronomical year -1 corresponding to 2 BC, and so on.<ref>{{Cite web| title = Calendars | work = L.E. Doggett| access-date = 27 April 2021| url = http://charon.nmsu.edu/~lhuber/leaphist.html | archive-url = https://web.archive.org/web/20120210184836/http://charon.nmsu.edu/~lhuber/leaphist.html | url-status = dead | archive-date = 10 February 2012 }}</ref><ref>{{Cite web| title = Year Dating Conventions | work = National Aeronautics and Space Administration| access-date = 27 April 2021| url = https://eclipse.gsfc.nasa.gov/SEhelp/dates.html}}</ref>

{| class="wikitable" style="text-align:center;margin-left:auto; margin-right:auto; border:none;"
|+ Strict vs Popular usage
|-
! style="text-align:left;" | Year
! [[2 BC]]
! [[1 BC]]
! [[AD 1|1]]
! [[AD 2|2]]
! ...
! [[AD 99|99]]
! [[AD 100|100]]
! [[AD 101|101]]
! [[AD 102|102]]
! ...
! [[AD 199|199]]
! [[AD 200|200]]
! [[AD 201|201]]
! [[AD 202|202]]
! ...
! [[AD 1899|1899]]
! [[AD 1900|1900]]
! [[AD 1901|1901]]
! [[AD 1902|1902]]
! ...
! [[AD 1999|1999]]
! [[AD 2000|2000]]
! [[AD 2001|2001]]
! [[AD 2002|2002]]
! ...
![[AD 2025|2025]]
! ...
! 2099
! 2100
! 2101
! 2102
! ...
|-
! style="text-align:left;" | Strict
| colspan="2" style="background-color:#CEF2E0;" | [[1st century BC]]
| colspan="5" style="background-color:#CEF2E0;" | [[1st century]]
| colspan="5" style="background-color:#CEE0F2;" | [[2nd century]]
| colspan="2" style="background-color:#E0CEF2;" | [[3rd century]]
| ...
| colspan="2" style="background-color:#F2CEE0;" | [[19th century]]
| colspan="5" style="background-color:#F2E0CE;" | [[20th century]]
| colspan="7" style="background-color:#CEF2E0;" | [[21st century]]
| colspan="2" style="background-color:#CEE0F2;" | 22nd century
| ...
|-
! style="text-align:left;" | Popular
| colspan="2" style="background-color:#CEF2E0;" | [[1st century BC]]
| colspan="4" style="background-color:#CEF2E0;" | [[1st century]]
| colspan="5" style="background-color:#CEE0F2;" | [[2nd century]]
| colspan="3" style="background-color:#E0CEF2;" | [[3rd century]]
| ...
| colspan="1" style="background-color:#F2CEE0;" | [[19th century]]
| colspan="5" style="background-color:#F2E0CE;" | [[20th century]]
| colspan="7" style="background-color:#CEF2E0;" | [[21st century]]
| colspan="3" style="background-color:#CEE0F2;" | 22nd century
| ...
|}

== Alternative naming systems ==
{{unreferenced section|date=May 2016}}
Informally, years may be referred to in groups based on the hundreds part of the year. In this system, the years 1900–1999 are referred to as the ''nineteen hundreds'' (''1900s''). Aside from English usage, this system is used in [[Swedish language|Swedish]], [[Danish language|Danish]], [[Norwegian language|Norwegian]], [[Icelandic language|Icelandic]], [[Finnish language|Finnish]] and [[Hungarian language|Hungarian]]. The Swedish {{Lang|sv|nittonhundratalet}} (or {{Lang|sv|1900-talet}}), Danish {{Lang|da|nittenhundredetallet}} (or {{Lang|da|nittenhundredetallet}}), Norwegian {{Lang|no|nittenhundretallet}} (or {{Lang|no|1900-tallet}}),<ref>{{Citation |last=Bolstad |first=Erik |title=århundre |date=2024-06-18 |work=Store norske leksikon |url=https://snl.no/%C3%A5rhundre |access-date=2025-04-06 |language=no}}</ref> Finnish {{Lang|fi|tuhatyhdeksänsataaluku}} (or {{Lang|fi|1900-luku}}) and Hungarian {{Lang|hu|ezerkilencszázas évek}} (or {{Lang|hu|1900-as évek}}) refer unambiguously to the years 1900–1999. In Swedish, however, a century is in more rare cases referred to as {{Lang|sv|det n-te seklet/århundradet}} ("the n-th century") rather than {{Lang|sv|n-hundratalet}}, i.e. the 17th century is (in rare cases) referred to as {{Lang|sv|17:(d)e/sjuttonde århundradet/seklet}} rather than ''1600-talet'' and mainly also referring to the years 1601–1700 rather than 1600–1699;<ref>{{cite web | url=https://svenska.se/tre/?sok=sjuttonde&pz=1 | title=Sjuttonde &#124; svenska.se }}</ref> according to ''[[Svenska Akademiens ordbok]]'', {{Lang|sv|16:(d)e/sextonde århundradet}} may refer to either the years 1501–1600 or 1500–1599.<ref>{{cite web | url=https://svenska.se/tre/?sok=sextonde&pz=1 | title=Sextonde &#124; svenska.se }}</ref>

[[Italian language|Italian]] also has a similar system, but it only expresses the hundreds and omits the word for 'thousand'. This system mainly functions from the 11th to the 20th century: 
:{{Lang|it|il [[Quattrocento]]}} (that is 'the four hundred', the 15th century)
:{{Lang|it|il [[Cinquecento]]}} (that is 'the five hundred', the 16th century). 
These terms are often used in other languages when referring to the [[history of Italy]].

== Similar dating units in other calendar systems ==
While the century has been commonly used in the West, other cultures and calendars have utilized differently sized groups of years in a similar manner. The [[Hindu calendar]], in particular, summarizes its years into groups of 60,<ref>{{cite web|title=www.vedavidyalaya.com|url=http://www.vedavidyalaya.com/varsham.htm|access-date=4 September 2013|archive-url=https://web.archive.org/web/20131217233346/http://www.vedavidyalaya.com/varsham.htm|archive-date=17 December 2013|url-status=dead}}</ref> while the [[Aztec calendar]] considers groups of 52.<ref>{{cite web|title=www.aztec-history.com|url=http://www.aztec-history.com/aztec-calendar.html|access-date=4 September 2013}}</ref>

== See also ==
{{Wiktionary|century}}
{{Commons category multi|Centuries|Centennials}}
* [[Age of Discovery]]
* [[Ancient history]]
* [[Before Christ]] and [[Anno Domini]]
* [[Common Era]]
* [[Decade]]
* [[List of decades, centuries, and millennia]]
* [[Lustrum]]
* [[Middle Ages]]
* [[Millennium]]
* [[Modern era]]
* [[Saeculum]]
* [[Year]]

== Notes ==
{{NoteFoot}}

== References ==
{{Reflist}}

== Bibliography ==
* [ftp://ftp.loc.gov/pub/reference.guides/battle.centuries.txt ''The Battle of the Centuries'']{{dead link|date=May 2025|bot=medic}}{{cbignore|bot=medic}}, [[Ruth Freitag]], [[U.S. Government Printing Office]]. Available from the Superintendent of Documents, P.O. Box 371954, Pittsburgh, PA 15250- 7954. Cite stock no. 030-001-00153-9. Retrieved 3 March 2019.

{{Time measurement and standards}}

[[Category:100 (number)]]
[[Category:Centuries| ]]
[[Category:Units of time]]