Baptize
Middle English: via Old French from ecclesiastical Latin baptizare, from Greek baptizein ‘immerse, baptize’.
wiktionary
From Middle English baptisen, baptizen, from Old French baptiser, batisier, from Ecclesiastical Latin, Late Latin baptizāre, from Ancient Greek βαπτίζω(baptízō, “to immerse, plunge, baptize”).
etymonline
baptize (v.)
"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.