Baptistery
In Christian architecture the baptistery or baptistry (Old French baptisterie; Latin baptisterium; Greek βαπτιστήριον, 'bathing-place, baptistery', from βαπτίζειν, baptízein, 'to baptize') is the separate centrally planned structure surrounding the baptismal font. The baptistery may be incorporated within the body of a church or cathedral, and provided with an altar as a chapel.