Noun > Costume
(count)
1 : the clothes that are worn by someone (such as an actor) who is trying to look like a different person or thing
children in their Halloween costumes
a colorful clown costume
2 : the clothes worn by a group of people especially during a particular time in the past
a formal 18th-century Japanese costume
The dancers were dressed in their national costumes. (=the clothing that is traditional in their countries)
3 : British : SWIMSUIT
– costumed adjective
costumed actors