circuit breaker

American  

[sur-kit brey-ker] / ˈsɜr kɪt ˌbreɪ kər /

noun

circuit breakers plural

1. Also called breaker.  Electricity. a device for interrupting an electric circuit to prevent excessive current, as that caused by a short circuit, from damaging the apparatus in the circuit or from causing a fire.

2. Also called trading halt or trading curb.  Stock Exchange. a temporary halt in trading automatically imposed when stock prices reach a predetermined level, as to check panic selling.

3. a lockdown or set of tight restrictions imposed for a fixed, usually short period to halt the spread of a highly transmissible infection (often used attributively).

   Circuit breakers only succeed if additional measures are taken, such as contact tracing and increased testing.

4. Australia, New Zealand. an activity serving to relieve or distract from stresses that might otherwise overwhelm.

   Sometimes a day out of the office is the best circuit breaker after a tense week.

5. any property-tax relief measure that reduces or limits property taxes for certain eligible taxpayers, as those with low income or the elderly.

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circuit breaker British  

noun

1. Sometimes shortened to: breaker.  a device that under abnormal conditions, such as a short circuit, interrupts the flow of current in an electrical circuit Compare fuse 2

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circuit breaker Scientific  

1. A switch that automatically interrupts the flow of electric current if the current exceeds a preset limit, measured in amperes. Circuit breakers are used most often as a safety precaution where excessive current through a circuit could be hazardous. Unlike fuses, they can usually be reset and reused.

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Other Word Forms

Noun Inflected Forms

• circuit breakers
  plural

Etymology

Origin of circuit breaker

An Americanism dating back to 1870–75

Example Sentences

See Examples For:

circuit breaker

He said musicians at the venue described "smoke from a circuit breaker near the stage followed by the power going out and an explosion".

From Barron's ● Jul. 12, 2026

“Without a circuit breaker in sight and the U.S. out on holiday, the bearish dynamics could continue ahead of the weekend,” he said.

From The Wall Street Journal ● Jul. 3, 2026

"Notwithstanding the imposition of circuit breaker restrictions, the decision-making in Northern Ireland was chaotic," it said.

From BBC ● Nov. 20, 2025

None other than Justice Antonin Scalia wrote that the jury functions as “a circuit breaker in the state’s machinery of justice.”

From Slate ● Nov. 7, 2025

One day when I go downstairs to flip the circuit breaker, I catch Hunter on all fours, trying to walk like a vuvv, with his back to the floor.

From "Landscape with Invisible Hand" by M.T. Anderson