A statute is a formal written enactment of a legislative authority that governs a state, city, or county. Typically, statutes command or prohibit something, or declare policy. The word is often used to distinguish law made by legislative bodies from case law, decided by courts, and regulations issued by government agencies. Statutes are sometimes referred to as legislation or "black letter law". As a source of law, statutes are considered primary authority (as opposed to secondary).