calendar year

calendar +‎ year

calendar year (plural calendar years)

1. The length of time between the beginning and end of a year as marked on a calendar, such as from 0:00 January 1 to 24:00 December 31 in the Gregorian calendar.

• The average length of the calendar year in the Gregorian calendar is 365.2425 days (taking leap years into account). This is extremely close the average year length in other calendars such as the Islamic calendar based on the average time between vernal equinoxes (currently 365.2424 days and increasing), but slightly different from formula-based calendars such as the Jewish calendar which averages 365.2468 days.