ClipArt ETC
"A name given sometimes to a seperate building, sometimes to the portion of the church itself in which the ceremony of baptism was performed. In the latter case, the Baptistery was merely the enclosure containing the font, to be seen in most English churches. According to the earlier arrangements of the Christian Church, however, the Baptistery seems usually to have been a building standing detached from, though in the immediate vicinity of the church to which it appertained." — Chambers' Encyclopedia, 1875

Baptistery

"A name given sometimes to a seperate building, sometimes to the portion of the church itself in which…