Circuit Breaker

1. A circuit breaker is a device which can stop the flow of electricity around a circuit by switching itself off if anything goes wrong.
2. A device that under abnormal conditions, such as a short circuit, interrupts the flow of current in an electrical circuit.

An automatic device for stopping the flow of current in an electric circuit as a safety measure.

Sources:

Англійський словник Коллінза, електронний ресурс: https://www.collinsdictionary.com/

Словник Lexicoелектронний ресурс: www.lexico.com