noun
emergency buzzer; emergency alarm
Refers to a device that emits a loud sound to alert people in an emergency, such as in buildings, trains, or public facilities.
火災報知器の非常ブザーが鳴った。
The emergency buzzer of the fire alarm went off.
駅のホームで非常ブザーが押された。
The emergency buzzer was pressed on the station platform.
Compound of 非常 (emergency) and ブザー (buzzer, from English).