one, 1 / the first in order, foremost / the beginning / the best / a kind of; one of something / (card games) an ace / unity / the bottom string of a shamisen or other Japanese musical instrument

one person

one day

each person

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

(literally) one side / everywhere, all around, the whole area / one viewpoint, one opinion or way of thinking / the front page of a newspaper

Alternative form of 一々

(monarchy) an East Asian practice of dating, using exactly one distinct era name for each monarch's reign, where such era name also eventually becomes the monarch's posthumous name

(rare) the first day of the month

once; one time