common law

/ˌkɑmən ˌˈlɔ/

/ˈkɒmən lɔ/

Other forms: common laws

Common law is based on decisions judges made in the past, rather than on written statutes. The requirement that police officers read someone's rights as they're being arrested is based in common law.

The Miranda warnings that arresting officers are required to give anyone they detain, beginning with "You have the right to remain silent," is a great example of common law. There are legal precedents proving that judges agree these warnings are constitutionally necessary; it's been decided in courtrooms, rather than established as a written law. You can also call common law case law or judicial precedent.

Definitions of common law

1. noun

   (civil law) a law established by following earlier judicial decisions
   synonyms: case law, precedent

   type of:

   civil law

   the body of laws established by a state or nation for its own regulation
2. noun

   a system of jurisprudence based on judicial precedents rather than statutory laws
   “common law originated in the unwritten laws of England and was later applied in the United States”

   synonyms: case law, precedent

   type of:

   jurisprudence, law

   the collection of rules imposed by authority