a year

one person / singleness, singularity / one's own efforts or strengths / an unmarried person, single

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

years

a grade, a school year / a year

year

one for all, all for one

each person

nth-year student or pupil