Definition of "Costume" :
noun: the attire worn in a play or at a fancy dress ball
"He won the prize for best costume."
noun: the attire characteristic of a country or a time or a social class
"He wore his national costume."
noun: unusual or period attire not characteristic of or appropriate to the time and place
"In spite of the heat he insisted on his woolen costume."
noun: the prevalent fashion of dress (including accessories and hair style as well as garments)
verb: dress in a costume
verb: furnish with costumes; as for a film or play