At the federal level, a circuit court is the layer of appellate courts situated between the federal district (trial) courts and the Supreme Court.
A federal circuit is composed of several districts.
At the state and local level, the name circuit court is given to trial courts as well as appellate courts, depending on the jurisdiction.
The name originated at common law when judges would travel from location to location in a “circuit” holding court at each.
[ Glossary ]