What is meant by a circuit?
A circuit is the actual or intended path of current between points of differing voltage. In the case of a household 120 volt circuit, the path is through a “hot” wire from the breaker, an item that is using the electricity, and a “neutral” wire connected to the grounded neutral bar in the panel. In a sense each loop that current makes (through a single light and its switch, for instance) is a circuit but the most common meaning is the “branch circuit”, that is, everything fed (or interrupted) by a given breaker or fuse. See Your electrical system.
