Volume 1: 1771 Edition of the Encyclopedia Britannica!
Baptistery
Baptistery, in ecclesiastical writers, a place in which the ceremony of baptism is performed. In the ancient church, it was one of the exedrae, or buildings, distinct from the church itself, and consisted of a porch or anti-room, where the persons to be baptized made their confession of faith; and an inner room where the ceremony of baptism was performed.