LAW:  That which is laid down, ordained, or established.  A rule or method according to which phenomena or actions co-exist or follow each other.  Law, in its generic sense, is a body of rules of action or conduct prescribed by controlling authority, and having binding legal force. 

Black's Law Dictionary (1990)

John Austin († 1859)  Legal Positivism

The Province of Jurisprudence Determined (1832)