an underground channel or tunnel with a rectangular cross-section

to study / to learn

a box-shaped receptacle, e.g. a coin bank or letter box (e.g. 銭函, 投函する) / to insert [into a container] (cf. 入れる, 容れる) / a suit of armor (more commonly 鎧)

history / the study of history

(chiefly women's speech) first person singular pronoun: I, me

(polite) first-person singular pronoun: I, me

a personal or private matter / (by extension) selfishness

(formal) first-person singular pronoun: I, me

personal, private / secret

a personal or private matter / selfishness / privacy, secrecy / (women's speech, obsolete) a brother-in-law