use one thing for many purposes / work someone hard

to use one's head

to remember, to recognize, to look familiar

everything

(colloquial) current boyfriend

(slang) Alternative form of 彼氏 (kareshi, “boyfriend”)

everyone, one and all

(physics, chemistry) atomic number

a postal code, a zip code

number (on an athlete's uniform's back); jersey number, uniform number, player number, shirt number