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

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

(rare, obsolete) (all senses appear to be identical as for hitohi above)

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

dotting the i's and crossing the t's

happening once a year

(mahjong) determining what tile would complete an opponent's hand

(typography) each mark of the pairs of iteration marks ゝ/ゞ and ヽ/ヾ, respectively used to repeat 清音 (seion)/濁音 (dakuon) hiragana and katakana

in kambun, a type of kaeriten in which the reading order is marked with numbers 1, 2, 3... indicating the order

(dated) something that stands out among many other things / (figuratively) a single woman among many men