alarm bell; emergency alarm
Refers to a bell or audible alarm used in emergencies, such as fire alarms or security alerts.
If a fire breaks out, please sound the emergency alarm immediately.
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'.