costume

/ˈkɑs·tum/ n [C/U]

Definition

› a set of clothes worn in order to look like someone else, esp. for a party or as part of an entertainment: [C] a clown costume › A costume is also the set of clothes typical of a particular country or period of history: [U] The dancers dressed in national costume.

(Definition of costume n from the Cambridge Academic Content Dictionary © Cambridge University Press)