'baptize' originates from Greek, specifically the word 'baptizein', where the root 'bapti-' meant 'to dip, immerse'.

'baptize' passed into Late Latin as 'baptizare', then into Old French as 'baptiser', and was adopted into Middle English; the agent noun 'baptizer' was formed in English by adding the suffix '-er' to the verb 'baptize'.

Initially it meant 'to dip or immerse'; over time it came to mean the religious act of administering baptism and now also broadly 'to perform a baptism' (whether by immersion, pouring, or sprinkling).