English Reference
noun

circuit breaker

n.

  1. 01 B2 Upper Intermediate Technical

    a switch that automatically stops electricity from flowing if the system becomes overloaded or dangerous.

    an automatically operated electrical switch designed to protect an electrical circuit from damage caused by excess current from an overload or short circuit.

    Simple

    The power went out because the circuit breaker tripped when I turned on the heater.

    In context

    Modern residential units are equipped with sensitive circuit breakers that instantly disconnect power if they detect a ground fault or a significant surge.

    Usage

    Often used with the verb 'trip' when the device activates automatically.

    fusesafety switch
  2. 02 C1 Advanced Technical

    a rule that stops trading on the stock market for a short time if prices fall too fast.

    a regulatory measure that temporarily halts trading on an exchange to prevent panic selling and extreme volatility.

    Simple

    The stock market hit a circuit breaker after prices dropped ten percent in one hour.

    In context

    Exchange authorities triggered the circuit breaker to allow investors a cooling-off period during the unprecedented market volatility.

    Usage

    Commonly used in financial journalism and stock market reporting.

    trading curbhalt
  3. 03 C1 Advanced Technical Computing

    a way of writing computer code that stops a program from trying to do something that is already failing.

    a design pattern used in modern software development to detect failures and encapsulate the logic of preventing a failure from constantly recurring.

    Simple

    The developer added a circuit breaker to the app so it wouldn't crash while the database was down.

    In context

    Implementing a circuit breaker pattern is essential for maintaining system stability in microservices architectures when a downstream service becomes unresponsive.

  4. 04 B2 Upper Intermediate British EnglishDialect

    a short, strict set of rules that stops people from moving around to prevent a virus from spreading.

    a temporary, intensive period of restrictions on movement and social contact designed to interrupt the transmission of a contagious disease.

    Simple

    The government announced a two-week circuit breaker to lower the number of new infections.

    In context

    Public health officials debated whether a short circuit breaker would be sufficient to reduce the hospitalisation rate during the winter wave.

    Teacher's tip

    This term became widely used in the UK and Singapore during the COVID-19 pandemic as a less harsh-sounding alternative to 'lockdown'.

    lockdownquarantine

A compound of the noun circuit, from the Old French circuit, and the agent noun breaker, derived from the Old English brecan. The term describes the mechanical interruption of an electrical loop.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Level B2 · Upper Intermediate
Updated