1. (noun)year, twelvemonth, yr a period of time containing 365 (or 366) days
"she is 4 years old"; "in the year 1920"
2. (noun)year a period of time occupying a regular part of a calendar year that is used for some particular activity
"a school year"
3. (noun)year the period of time that it takes for a planet (as, e.g., Earth or Mars) to make a complete revolution around the sun
"a Martian year takes 687 of our days"
4. (noun)class, year a body of students who graduate together
"the class of '97"; "she was in my year at Hoehandle High"