A more thorough explanation:

Definition: The law of the circuit refers to the legal precedent set by a U.S. Circuit Court of Appeals. This means that the decisions made by a Circuit Court of Appeals must be followed by lower courts within that same circuit.

For example, if the Ninth Circuit Court of Appeals rules on a case, all lower courts within the Ninth Circuit must follow that ruling. However, a ruling by the Ninth Circuit does not necessarily apply to courts in other circuits.

This law helps to ensure consistency and predictability in the legal system. It also allows for efficient resolution of cases, as lower courts can rely on the precedent set by higher courts within their circuit.