Common Law Definition

A legal system derived from the broad and comprehensive principles encompassed within the unwritten laws of England and applied in most English-speaking countries, including the United States (except the state of Louisiana). The principles are created and modified by judicial decisions; passed on through custom, traditional usage, and precedent; are adaptable when applied to new facts and circumstances; and are changeable when required. Although much of what was once part of the common law, such as commercial law and criminal law, has been codified, other areas of the law, such as contract law, property law, and tort law, are still primarily governed by the principles of the common law. See also case law, casus omissus, civil law, and natural law.

(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.