noun
car horn; alarm; audible warning device
A device that produces a loud sound as a warning, typically a car horn or an alarm. Often used in technical or legal contexts.
車の警音器が故障して、音が出なくなった。
The car's horn broke and stopped making sound.
この工場には火災を知らせる警音器が設置されている。
This factory is equipped with an alarm to signal fires.
警報器 is a broader term for any alarm device, while 警音器 specifically emphasizes sound.
Compound of 警 (warning), 音 (sound), and 器 (device). A straightforward technical term.