Editing Fortnight

{{short description|Time period of two weeks}}
{{about|the unit of time measurement|the video game|Fortnite|other uses|Fortnight (disambiguation)}}
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{{Use dmy dates|date=August 2016}}
A '''fortnight''' is a unit of time equal to 14 [[day]]s (two [[week]]s). The word derives from the [[Old English]] term {{lang|ang|fēowertīene niht}}, meaning "{{Transliteration|ang|fourteen [[Night#Duration and geography|nights]]}}" (or "fourteen days", since the Anglo-Saxons counted by nights).<ref>{{cite news|title=Fortnight|work=The Concise Oxford Dictionary|edition= 5th|date= 1964|page= 480}}</ref><!-- contraction of M.E. ''fourteniht'', from O.E. ''feowertyne niht'', lit. "fourteen nights", preserving the ancient Germanic custom of reckoning by nights, mentioned by [[Tacitus]] in "Germania" xi. Related: Fortnightly. The fortnight is a unit of time equal to 14 days, e.g., "I'm meeting Adam in Venice in a fortnight" --><ref>''Senight'', ''sennight'' or ''se'night'' (seven-night), an old word for the week, was still in use in the early 19th century, to judge from [[Jane Austen]]'s letters.</ref>

==Astronomy and tides==
{{further|Eclipse cycle}}
<!-- Lunar fortnight redirects here -->
In [[astronomy]], a ''lunar fortnight'' is half a [[Lunar month#Synodic month|lunar synodic month]], which is equivalent to the [[arithmetic mean|mean]] period between a full moon and a new moon (and vice versa). This is equal to 14.77 days.<ref name="totality">{{cite book |last=Littmann |first=Mark |author2=Fred Espenak |author3=Ken Willcox |title=Totality: Eclipses of the Sun |publisher=[[Oxford University Press]] |year=2008 |isbn=978-0-19-953209-4}}</ref><ref>{{cite web |url=http://scienceworld.wolfram.com/astronomy/SynodicMonth.html |title=Synodic Month definition |first=Eric W. |last=Weisstein}}</ref>
It gives rise to a lunar fortnightly [[tidal constituent]] (see: [[Long-period tides]]).

==Analogs and translations==
In many languages, there is no single word for a two-week period, and the equivalent terms "two weeks", "14 days", or "15 days" ([[inclusive counting|counting inclusively]]) have to be used.

* [[Celtic languages]]: in [[Welsh language|Welsh]], the term ''pythefnos'', meaning "15 nights", is used. This is in keeping with the Welsh term for a week, which is ''wythnos'' ("eight nights").<ref>{{cite web |author1=BBC |title=BBC Wales - Catchphrase|url=http://www.bbc.co.uk/wales/catchphrase/ysbyty_brynaber/lessons/language/lang45.shtml|website=BBC Wales|access-date=18 November 2016|date=16 October 2014|quote=Wythnos is a week.}}</ref> In [[Irish language|Irish]], the term is ''coicís''.
* Similarly, in [[Greek language|Greek]], the term δεκαπενθήμερο (''dekapenthímero''), meaning "15 days", is used.
* The [[Hindu calendar]] uses the [[Sanskrit]] word पक्ष "pakṣa", meaning one half of a [[lunar month]], which is between 14 and 15 solar days.
* In [[Romance languages]] there are the terms ''quincena'' (or ''quince días'') in [[Galician language|Galician]] and [[Spanish language|Spanish]], ''quinzena'' or ''quinze dies'' in [[Catalan language|Catalan]] and ''quinze dias'' or ''quinzena'' in [[Portuguese language|Portuguese]], ''quindicina''{{Citation needed|date=January 2025|reason="Quindicina", in Italian language, actually means 15 days, not 14; it comes from the word for "15"}} in [[Italian language|Italian]], ''[[:wikt:fr:quinze jours|quinze jours]]'' or ''[[:wikt:fr:quinzaine|quinzaine]]'' in [[French language|French]], and ''chenzină'' in [[Romanian language|Romanian]], all meaning "a grouping of 15".
* [[Semitic languages]] have a "doubling [[suffix]]". When added at the end of the word for "week" it changes the meaning to "two weeks". In [[Hebrew language|Hebrew]], the single-word ''שבועיים'' (''shvu′ayim'') means exactly "two weeks". Also in [[Arabic language|Arabic]], by adding the common [[Dual (grammatical number)#Arabic|dual suffix]] to the word for "week", ''أسبوع'', the form ''أسبوعين'' (''usbu′ayn''), meaning "two weeks", is formed.
* [[Slavic languages]]: in [[Czech language|Czech]] the terms ''čtrnáctidenní'' and ''dvoutýdenní'' have the same meaning as "fortnight".<ref>{{cite web|url=https://www.indifferentlanguages.com/words/fortnight|title=Do You Know How to Say Fortnight in Different Languages?|website=www.indifferentlanguages.com}}</ref> In [[Ukrainian language|Ukrainian]], the term ''два тижні'' is used in relation to "biweekly, two weeks".

==See also==
{{Wiktionary|fortnight}}
* [[FFF system]]
* [[Half-month]]
* [[Sennight]]
* [[Roman calendar#Days|Ides]] (''idus''), Roman day for the midst of a month.

==References==
{{Reflist}}

{{Time measurement and standards}}

[[Category:Units of time]]