The Collaborative International Dictionary of English v.0.48:
backdrop \back"drop\ n. 1. the scenery hung at back of stage. Also called in Britain backcloth. Syn: background, backcloth [WordNet 1.5] 2. the background, setting, or circumstances of an event; as, the backdrop for the summit meeting. [PJC]WordNet (r) 3.0 (2006):
backcloth n 1: scenery hung at back of stage [syn: backdrop, background, backcloth]