A downstage drapery whose movement is used to signal the beginning or end of an act. Also called House Curtain or Main Rag, though there are minor distinctions. A house curtain is owned and permanently installed at the theatre, and is thus generic. House curtain of Hamman Hall, Rice Univ., Houston, TX. An act curtain, which may also be called a show curtain, is specific to the production. Wicked show curtain. Again, a subtle difference between Act Curtain and Show Curtain: occasionally, a production will have different drops for each act.