silencer
n
(a) (Brit) (US muffler) device that reduces the noise made by a vehicle´s exhaust (机动车的)消声器. =>illus at App 1 见附录1插图, page xii.
(b) device that reduces the noise made by a gun being fired (枪的)消声器. silence interj be quiet 安静; 别出声
`Silence!´ shouted the teacher. `安静!'教师喊道.