Costume

Stage clothes is a term for any clothes used by performers on stage. The term is sometimes used only for those clothes which are specially made for the stage performance by a costume designer or picked out by a costume coordinator. Theatrical costumes can help actors portray characters' age, gender role, profession, social class, personality, and even information about the historical period/era, geographic location, time of day, as well as the season or weather of the theatrical performance. Stage clothes may be used to portray a historical look or they can be used to exaggerate some aspect of a character.

From Wikipedia