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

three years; triennial / three years old

Alternative form of 青年: a youth, a young man

a millennium; a thousand years

chronology

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

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)

(idiomatic) to age, to get older

a dynasty

a fountain pen