1. Members of Parliament making a point of order in the house of Commons wear a collapsible opera hat and nobody sniggers.
    在下议院，提出程序问题的议员们戴一种折叠式的大礼帽也无人窃笑。

2. opera hat

2. A costume drama: the traditional drama clothing, knives, guns, sword, halberd, opera hat, armor, modern and folk dance costumes, props and performances.
    传统戏剧服装、刀、枪、剑、戟、戏帽、盔甲，现代及民间舞蹈服装、演出道具。