one day

(rare) the first day of the month

a year

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

one day, 24 hours / the daytime, the period from dawn until dusk / (figuratively) a short period of time / one day, someday, an unspecified day / the first day of the month

all day

the first day of the month (solar or lunar calendar)

(literary) one day, 24 hours / (literary) the daytime, the period from dawn until dusk / (literary) (figuratively) a short period of time

(obsolete) one day, 24 hours / (obsolete) the daytime, the period from dawn until dusk