common law

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Law established by court decisions rather than by statutes enacted by legislatures.
• noun The law of England adopted by its territories and colonies, including the United States at the time of its formation.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun law Law developed by judges through decisions of courts and similar tribunals (also called case law), as distinguished from legislative statutes or regulations promulgated by the executive branch.
• noun law typically in the phrase "common law system" -- a legal system that gives great precedential weight to common law (in sense 1), as opposed to a civil law, Islamic law, and Soviet law systems.
• noun law typically in the phrase "common law jurisdiction" -- a jurisdiction that uses a common law system (in sense 2), United Kingdom and most of its former colonies and possessions, including the United States.
• noun law (archaic) one of two legal systems in England and in the United States before 1938 (the other being "equity").

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• adjective based on common law
• noun (civil law) a law established by following earlier judicial decisions
• noun a system of jurisprudence based on judicial precedents rather than statutory laws