n. 背景

[ noun ]
scenery hung at back of stage
<noun.artifact>

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]