Editing Calendar (section)

{{Short description|System for organizing the days of year}}
{{About|the dating system|the physical object|Calendar (stationery)|other uses|Calendar (disambiguation)}}
{{Redirect|📅|the unofficial holiday commonly represented by this emoji|World Emoji Day}}
{{Distinguish|Calender}}
{{Globalize|2=Eurasia|3=the Near East|date=September 2022|talk=Talk:Calendar#Systemic bias towards Eurasian calendars}}
{{Use dmy dates|date=March 2021}}
{{Use American English | date = November 2020}}
{{Calendar|lk=on|show_year=on|float=right|month=current}}
[[File:Kalender Indonesia.jpg|thumb|Modern day [[Indonesia]]n [[Gregorian calendar]] for a [[Catholic Church|Catholic]] [[Church (building)|church]]]]
[[File:Calendar (part of a set) MET DP-13486-011.jpg|thumb|250px|British calendar, 1851, gilt bronze and [[malachite]], height: 20.3&nbsp;cm, [[Metropolitan Museum of Art]] (New York City)]]

A '''calendar''' is a system of organizing [[day]]s. This is done by giving names to periods of [[time]], typically days, [[weeks]], [[month]]s and [[years]].<ref>{{Cite web |title=Calendars and their History |url=https://eclipse.gsfc.nasa.gov/SEhelp/calendars.html |access-date=2024-03-12 |website=eclipse.gsfc.nasa.gov}}</ref><ref>{{Cite book |last=Guo |first=Rongxing |url=https://books.google.com/books?id=8QNbDwAAQBAJ&dq=A+calendar+is+a+system+of+organizing+days.+This+is+done+by+giving+names+to+periods+of+time,+typically+days,+weeks,+months+and+years.&pg=PA159 |title=Human-Earth System Dynamics: Implications to Civilizations |date=2018-05-16 |publisher=Springer |isbn=978-981-13-0547-4 |pages=159 |language=en}}</ref><ref>{{Cite book |last1=Bond |first1=Thomas |url=https://books.google.com/books?id=ADJEAgAAQBAJ&dq=A+calendar+is+a+system+of+organizing+days.+This+is+done+by+giving+names+to+periods+of+time,+typically+days,+weeks,+months+and+years.&pg=RA1-PA9 |title=Singapore PSLE Mathematics Challenging Practice Solutions (Yellowreef) |last2=Hughes |first2=Chris |date=2013-12-03 |publisher=Yellowreef Limited |isbn=978-0-7978-0222-3 |language=en}}</ref> A [[calendar date|date]] is the designation of a single and specific day within such a system. A calendar is also a physical record (often paper) of such a system. A calendar can also mean a list of planned events, such as a [[court calendar]], or a partly or fully chronological list of documents, such as a calendar of wills.

Periods in a calendar (such as years and months) are usually, though not necessarily, synchronized with the cycle of the [[solar calendar|sun]] or the [[lunar calendar|moon]].<ref>{{Cite web |date=2021-02-12 |title=Do menstrual and lunar cycles synchronize? What scientists say |url=https://www.medicalnewstoday.com/articles/menstrual-cycles-and-lunar-cycles-is-there-a-link |access-date=2024-03-12 |website=www.medicalnewstoday.com |language=en}}</ref><ref name="Introduction to Calendars">{{Cite web |title=Introduction to Calendars |url=https://aa.usno.navy.mil/faq/calendars |access-date=2024-03-12 |website=aa.usno.navy.mil}}</ref><ref>{{Cite web |title=History – Ancient Egyptian Calendar |url=https://mabscross.co.uk/wp-content/uploads/2020/06/3.-History-Calendar.pdf |access-date=2024-03-12}}</ref> The most common type of pre-modern calendar was the [[lunisolar calendar]], a lunar calendar that occasionally adds one [[intercalary month]] to remain synchronized with the [[solar year]] over the long term.