Noun
1. the attire worn in a play or at a fancy dress ball;
"he won the prize for best costume"2. 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"3. the prevalent fashion of dress (including accessories and hair style as well as garments)
4. the attire characteristic of a country or a time or a social class;
"he wore his national costume"