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

entirely, quite; completely; just like, so to speak, as though, as if

(literally) a carriage horse / (figuratively) a person absorbed in work and blind to all else

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

to work at a job, to labour / to work properly, to operate, to function; to carry out one's function, to be effective, to come into play / to perpetrate or commit a crime