kanji approved for regular use by the 文部科学省 (Monbu-kagaku-shō, “Japanese Ministry of Education”)

one day

(rare) the first day of the month

幾日も幾日も: day after day

to recall, to remember / to learn / to memorize / to feel (an emotion or sense)

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

he / distal demonstrative, something far off removed from both speaker and listener: that / boyfriend

distal demonstrative, something far off removed from both speaker and listener: that, yon / particularly, male personal third person pronoun: he / by extension from he: boyfriend

he; boyfriend

all day