Meaning : The attire worn in a play or at a fancy dress ball.
Example :
He won the prize for best costume.
Meaning : Unusual or period attire not characteristic of or appropriate to the time and place.
Example :
In spite of the heat he insisted on his woolen costume.
Meaning : The prevalent fashion of dress (including accessories and hair style as well as garments).
Meaning : The attire characteristic of a country or a time or a social class.
Example :
He wore his national costume.