# Calendar

By [xWhiteOuroboros](https://paragraph.com/@xwhiteouroboros) · 2023-08-20

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A **calendar** is a system of organizing days. This is done by giving names to periods of [time](https://en.wikipedia.org/wiki/Time), typically [days](https://en.wikipedia.org/wiki/Day), [weeks](https://en.wikipedia.org/wiki/Week), [months](https://en.wikipedia.org/wiki/Month) and [years](https://en.wikipedia.org/wiki/Year). A [date](https://en.wikipedia.org/wiki/Calendar_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](https://en.wikipedia.org/wiki/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 [sun](https://en.wikipedia.org/wiki/Solar_calendar) or the [moon](https://en.wikipedia.org/wiki/Lunar_calendar). The most common type of pre-modern calendar was the [lunisolar calendar](https://en.wikipedia.org/wiki/Lunisolar_calendar), a lunar calendar that occasionally adds one [intercalary month](https://en.wikipedia.org/wiki/Intercalary_month) to remain synchronized with the [solar year](https://en.wikipedia.org/wiki/Solar_year) over the long term.

![](https://storage.googleapis.com/papyrus_images/3ac582c6f806160db8d531ca37d2172919d793a9d95d25ab4fe23dbfa935ee89.png)

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*Originally published on [xWhiteOuroboros](https://paragraph.com/@xwhiteouroboros/calendar)*