"to administer the rite of baptism to," c. 1300, from Old French batisier "be baptized; baptize; give a name to" (11c.), from Latin baptizare, from Greek baptizein "immerse, dip in water," also figuratively, "be over one's head" (in debt, etc.), "to be soaked (in wine);" in Christian use, "baptize;" from baptein "to dip, steep, dye, color," perhaps from PIE root *gwabh- (1) "to dip, sink." Christian baptism originally was a full immersion. Related: Baptized; baptizing.