a period of 365 or 366 days, in the Gregorian calendar, divided into 12 calendar months, now reckoned as beginning Jan. 1 and ending Dec. 31 (calendar year or civil year) Compare common year, leap year.
a period of approximately the same length in other calendars.
a space of 12 calendar months calculated from any point: This should have been finished a year ago.
Astronomy. Also called lunar year. a division of time equal to 12 lunar months. Also called astronomical year, equinoctial year, solar year, tropical year. a division of time equal to about 365 days, 5 hours, 48 minutes, and 46 seconds, representing the interval between one vernal equinox and the next. Also called sidereal year. a division of time equal to the equinoctial year plus 20 minutes, representing the time required for the earth to complete one revolution around the sun, measured with relation to the fixed stars. Compare anomalistic year.
the time in which any planet completes a revolution round the sun: the Martian year.