full-fledged, qualified, up to standard / adulthood, behaving like an adult or as a member of the society / Used other than figuratively or idiomatically: see 一人, 前. ("one person's portion")

a handful / a small amount

a bath (a single instance of taking a bath)

a (single) branch of flowers / a (single) cloud

a (single) blast of air (wind, etc.)

a (single) leaf / (figuratively) a (single) small boat / a (single) sheet (something thin: page, etc.)

a (single) bowl (of rice) / a (single) pair of chopsticks

a (single) meal / a (single) bowl of rice

a (single) battle, match, fight

to fight a single match