A canon (from the Latin canonicus, itself derived from the Greek κανονικός, kanonikós, "relating to a rule", "regular") is a member of certain bodies subject to an ecclesiastical rule.Originally, a canon was a cleric living with others in a clergy house or, later, in one of the houses within the precinct of or close to a cathedral and conducting his life according to the orders or rules of the church. This way of life grew common (and is first documented) in the eighth century.