coulisse
/kuːˈliːs/noun
1- a flat piece of scenery at the side of the stage in a theatre（戏台）侧面布景。
1.1
the coulisses
the spaces between these pieces of scenery; the wings（戏台）两侧布景间的空地; 侧台。
词源
early 19th cent.: French, feminine of coulis 'sliding', based on Latin colare 'to flow'.