Baptistery

In Christian architecture the baptistry or baptistery (Latin baptisterium, from Greek βαπτίζειν) is the separate centrally-planned structure surrounding the baptismal font. The baptistry may be incorporated within the body of a church or cathedral and be provided with an altar as a chapel. In the early Church, the catechumens were instructed and the sacrament of baptism was administered in the baptistery.