noun

1. 1. a period of 365 days (in a leap year, 366 days) divided into 12 months and regarded in the Gregorian calendar as beginning Jan. 1 and ending the following Dec. 31
   2. a period of more or less the same length in other calendars
2. the period (365 days, 5 hours, 48 minutes, and 46 seconds of mean solar time) spent by the sun in making its apparent passage from vernal equinox to vernal equinox: the year of the seasons
   also tropical year or equinoctial year or solar year
3. the period (365 days, 6 hours, 9 minutes, and 9.54 seconds of mean solar time) spent by the sun in its apparent passage from a fixed star and back to the same position again: it is the true period of the earth's revolution, and the difference in time between this and the tropical year is due to the precession of the equinoxes
   also sidereal year
4. a period of 12 lunar months, as in the Jewish calendar
   also lunar year
5. the period of time occupied by any planet in making one complete revolution from perihelion to perihelion: for the earth this period is 365 days, 6 hours, 13 minutes, and 53 seconds: it is slightly longer than the sidereal year due to the extra time needed to reach an advancing perihelion, the lag being caused by the gravitational pull of the other planets
   also anomalistic year
6. a period of 12 calendar months reckoned from any date a year from today
7. a calendar year of a specified number in a particular era the year 500
8. a particular annual period of less than 365 days a school year
9. 1. age old for his years
   2. time; esp., a long time he died years ago

Etymology: ME yere < OE gear, akin to Ger jahr < IE *yēro-, year, summer (> Gr hōros, time, year, OSlav jara, spring) < base *ei-, to go (> L ire, to go): basic sense “that which passes”