noun
alarm bell; emergency alarm
Refers to a bell or audible alarm used in emergencies, such as fire alarms or security alerts.
火事が起きたら、すぐに非常ベルを鳴らしてください。
If a fire breaks out, please sound the emergency alarm immediately.
非常ベルが突然鳴り出して、みんな驚いた。
The alarm bell suddenly went off and everyone was surprised.
Compound of 非常 (emergency) and ベル (bell). The word 非常 is a Sino-Japanese term meaning 'emergency' or 'extraordinary', and ベル is a loanword from English 'bell'.