enter

mailbox

a letter, epistle (written message or note) / (archaic) a utility paper used for various purposes, such as for jotting down notes or for wrapping items

(Kagoshima dialect) a letter, epistle (written message or note)

to go in; to come in / 要る: to be necessary, to be required

to enter, go into, get into a place or a thing / to join a group or organization / to be contained (in), to be included (in) / to be a member of a group, set, category

expenses

sneak into, slip into

to obtain, to come into possession, to become available

to be proficient, skilled, experienced