velarium
/vɪˈleərɪəm/noun
(pl. velaria /-rɪə/)
- a large awning of a type used in ancient Rome to cover a theatre or amphitheatre as a protection against the weather, now more commonly used as an inner ceiling to improve acoustics（古罗马露天剧场的）天幕; 篷帐（现多用作室内棚顶以改进音响效果）。
词源
Latin.