Judiciary
The judiciary or judicial system is the system of courts that administers (or makes decisions about) justice. This kind of system, does its work in the name of the state (or country) or the sovereign. A judicial system is used to resolve disputes.
The term is also used to refer collectively to the judges and magistrates who form the basis of the judiciary, as well as the other people who help keep the system running properly.
Separation of powers
Separation of powers causes separate branches of government that each has a different purpose. The judiciary is the branch of government that interprets the law. Such systems may have three branches: Legislature, Executive and Judiciary. Often the judiciary branch has courts of first resort, appellate courts, and a supreme court or constitutional court. Decisions of the lower courts may be appealed to the higher courts.
Judiciary in the USA
In the United States the federal Judicial Branch is an integrated system of courts headed by the Supreme Court of the United States. Each state also has a judicial system.