Calendar

November
Su Mo Tu We Th Fr Sa
01 02
03 04 05 06 07 08 09
10 11 12 13 14 15 16
17 18 19 20 21 22 23
24 25 26 27 28 29 30
2024
Modern day Indonesian Gregorian calendar for a Catholic church
British calendar, 1851, gilt bronze and malachite, height: 20.3 cm, Metropolitan Museum of Art (New York City)

A calendar is a system of organizing days. This is done by giving names to periods of time, typically days, weeks, months and years.[1][2][3] A 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 sun or the moon.[4][5][6] 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.

  1. ^ "Calendars and their History". eclipse.gsfc.nasa.gov. Retrieved 12 March 2024.
  2. ^ Guo, Rongxing (16 May 2018). Human-Earth System Dynamics: Implications to Civilizations. Springer. p. 159. ISBN 978-981-13-0547-4.
  3. ^ Bond, Thomas; Hughes, Chris (3 December 2013). Singapore PSLE Mathematics Challenging Practice Solutions (Yellowreef). Yellowreef Limited. ISBN 978-0-7978-0222-3.
  4. ^ "Do menstrual and lunar cycles synchronize? What scientists say". www.medicalnewstoday.com. 12 February 2021. Retrieved 12 March 2024.
  5. ^ "Introduction to Calendars". aa.usno.navy.mil. Retrieved 12 March 2024.
  6. ^ "History – Ancient Egyptian Calendar" (PDF). Retrieved 12 March 2024.