The term Vatican Rules is a reference to the laws and regulations that govern the Catholic Church, which is headquartered in the Vatican City. The crossword solution for this term is 'Papacies, ' which refers to the office of the Pope, who is the leader of the Catholic Church and the head of the Vatican City. Papacies is an 8-letter word that describes the power and authority of the Pope, who is the ultimate authority in the Catholic Church.