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, 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

一躍:

一約: / 一躍: / 一龠: a unit of volume equal to 1,200 millet grains

一躍:

power generation (electricity)

one day

一月: January / １月: January / 1月: January