silencer vs acoustic device

silencer and acoustic device both are nouns.

Word	Noun	Adjective	Verb	Adverb
silencer	Yes	No	No	No
acoustic device	Yes	No	No	No

As nouns, acoustic device is a hypernym of silencer; that is, acoustic device is a word with a broader meaning than silencer:

silencer: a tubular acoustic device inserted in the exhaust system that is designed to reduce noise
acoustic device: a device for amplifying or transmitting sound

silencer (noun)	acoustic device (noun)
a tubular acoustic device inserted in the exhaust system that is designed to reduce noise	a device for amplifying or transmitting sound
short tube attached to the muzzle of a gun that deadens the sound of firing