Used other than figuratively or idiomatically: see 一, 発. / doing something only once / (baseball, informal) home run

(a duration of) one year / an unspecified year in the past

A solar year, the time it takes the Earth to complete one revolution of the Sun (between 365.24 and 365.26 days depending on the point of reference)

task; (doing a) bit of work / difficult task; hard work

(slang) the only choice, the one possible option

a male given name

one letter, one character

a surname

to start again from scratch

(informal) last one remaining (as of an item at the store, etc.)