A solar year, the time it takes the Earth to complete one revolution of the Sun (between 365.24 and 365.26 days depending on the point of reference)

(a duration of) one year / an unspecified year in the past

(idiomatic) to age, to get older

three years; the third year / (education) the third school year / (figuratively) a long period of time, several years

three years; triennial / three years old

mourning / loss

a natural number

(mathematics) root number

(graph theory) a number of vertices in a graph; order

(games) sudoku (a type of puzzle)