Glossary
Circuit court
In the federal system, a Court of Appeals: the intermediate level between the district courts and the U.S. Supreme Court. There are 13 federal Circuits. In some states, "circuit court" is also the name for the trial court.
The federal Circuits are organized geographically. The Sixth Circuit, for example, hears appeals from federal district courts in Tennessee, Kentucky, Michigan, and Ohio. The Ninth Circuit covers the West Coast. There's also a Federal Circuit that handles patents and certain specialty appeals from across the country.
A circuit's decisions bind all the federal district courts within it. They don't bind district courts in other circuits: which is why federal law sometimes develops differently in different parts of the country until the Supreme Court resolves the split.
In several states (Illinois, Tennessee, Florida, Virginia, others), "circuit court" is the name for the state-level trial court. Same word, completely different role.