'baptistery' originates from Medieval Latin, specifically the word 'baptisterium', where the Greek root 'baptist-' (from 'baptizein') meant 'to dip' or 'to immerse'.

'baptistery' changed from the Medieval Latin word 'baptisterium', which itself comes from Greek 'baptistērion' (βαπτιστήριον), and eventually became the modern English word 'baptistery'.

Initially, it meant 'a place for bathing or immersion (in the context of baptism)', and over time it has remained specialized as 'a place or building for performing baptisms'.