ˈkɑːˌstuːm 
British
ˈkɒˌstjuːm
plural costumes
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
always used before a noun
: involving people wearing costumes
You're invited to a costume party!
a costume ball
costume dramas [=movies that are set in the past in which the actors are dressed like people from the past]
Cite this Entry
“Costume.” Merriam-Webster.com Simple Definition, Merriam-Webster, https://www.merriam-webster.com/simple/costume. Accessed 17 Apr. 2026.
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