A circuit breaker is a safety pattern that temporarily stops an app from repeatedly calling a service that is failing. It gives the service time to recover instead of sending it more requests that are likely to fail.
Think of an electrical breaker that switches off when something is wrong, helping protect the rest of the house. In software, the app can pause calls and try again later.
The pattern can help a system recover, but it does not fix the underlying service problem. The app still needs a clear message or fallback while the service is unavailable.