're-baptisation' originates from the prefix 're-' (from Latin 're-' meaning 'again') combined with 'baptisation' (from 'baptize' + '-ation'), where 'baptize' ultimately derives from Greek 'baptizein'.

'baptize' comes from Greek 'baptizein' (to dip), which passed into Late Latin and Old French and then Middle English as 'baptizen'/'baptize'; the noun form developed with the suffix '-ation' and the prefix 're-' was later attached to form 're-baptisation' (and the variant spelling 're-baptization' in American English).

Initially related to the original sense 'to dip' or 'to immerse' (in the physical ritual), over time it became specialized to mean 'administering the baptismal rite' and, with the prefix 're-', 'administering that rite again' (or figuratively, a renewed initiation).