Saint Peter saint·pe·ter uncommon noun 1. disciple of Jesus and leader of the apostles; regarded by Catholics as the vicar of Christ on earth and first Pope SynonymsPeterSimon PeterSaint PeterSt. PeterSaint Peter the ApostleSt. Peter the Apostle Related words Word family Saint Peter's wreathSaint PetersburgSaint Peter the Apostle Broader terms Apostlesaint WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.