backcloth
noun (British English)(also backdrop British and North American English)
a painted piece of cloth that is hung behind the stage in a theatre as part of the scenery （舞台的）背景幕布 everything that can be seen around an event or scene （事件发生时）周围陪衬景物 the general conditions in which an event takes place, which sometimes help to explain that event （事态或活动的）背景