n.
1.a period of time containing 365 (or 366) days
2.a period of time occupying a regular part of a calendar year that is used for some particular activity
3.the period of time that it takes for a planet (as, e.g., Earth or Mars) to make a complete revolution around the sun
4.a body of students who graduate together
Idiom of the Day
at sea
to be on the sea, to be away on a voyage on the ocean
My grandfather was at sea for several months when he was a young man.