one day

the daytime, during the day / a half day, half of a day

(rare) the first day of the month

all day, throughout the day, sunrise to sunset, all around the clock

an effort, an endeavor

to endeavor, to make an effort

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

(collective, chiefly attributive) Japan and China

the daytime, during the day / noon, midday

solution, settlement / (music) Progression from dissonance to consonance; a chord to which such progression is made; resolution