In those hierarchically organised churches of Western Christianity which have an ecclesiastical law system, an ordinary is an officer of the church who by reason of office has ordinary power to execute the church's laws. The term comes from the Latin word ordinarius. In Eastern Christianity, a corresponding officer is called a hierarch, which comes from the Greek word ἱεράρχης meaning "priestly ruler". In common usage in the Episcopal Church, an ordinary is a diocesan bishop.