What does “costume” mean in Italian?

Costume does exist in Italian with the English sense: a costume di Carnevale is fancy dress. But left bare, in any sentence about the beach, a pool or a cruise, il costume is a swimsuit, short for costume da bagno. So hai preso il costume? is not asking about fancy dress — it’s “did you pack your swimming things?” The word covers trunks and one-pieces alike.

A two-piece is il due pezzi or il bikini. In another register il costume means custom or mores (il costume italiano, “Italian manners”), which is where the English theatrical sense ultimately comes from. In the clip a hopeful suitor is being teased about an imaginary cruise, and the question keeps circling back — “Il costume ce l’hai?” — because on the nave dell’amore the swimsuit is the whole point.