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
In one usage that is now archaic, but that gives insight into the history of the common law, "common law" referred to the pre-Christian system of law, imported by the Saxons to England, and dating to before the Norman conquest, and before there was any consistent law to be applied. That usage is obsolete today. It is both underinclusive and overinclusive, as discussed in the section on "misconceptions".