Common law
The common lawso named because it was "common" to all the king's courts across Englandoriginated in the practices of the courts of the English kings in the centuries following the Norman Conquest in 1066. The British Empire spread the English legal system to its historical colonies, many of which retain the common law system today. These "common law systems" are legal systems that give great precedential weight to common law, and to the style of reasoning inherited from the English legal system.
Common law
The first definition of "common law" given in "Black's Law Dictionary", 10th edition, 2014, is "The body of law derived from judicial decisions, rather than from statutes or constitutions; [synonym] CASELAW, [contrast] STATUTORY LAW." This usage is given as the first definition in modern legal dictionaries, is characterized as the “most common” usage among legal professionals, and is the usage frequently seen in decisions of courts. In this connotation, "common law" distinguishes the authority that promulgated a law. For example, the law in most Anglo-American jurisdictions includes "statutory law" enacted by a legislature, "regulatory law" (in the U.S.) or “delegated legislation” (in the U.K.) promulgated by executive branch agencies pursuant to delegation of rule-making authority from the legislature, and common law or "case law", "i.e.", decisions issued by courts (or quasi-judicial tribunals within agencies). This first connotation can be further differentiated into
Publication of decisions, and indexing, is essential to the development of common law, and thus governments and private publishers publish law reports. While all decisions in common law jurisdictions are precedent (at varying levels and scope as discussed throughout the article on precedent), some become "leading cases" or "landmark decisions" that are cited especially often.