BAPTISTRY
Etymology
Noun
baptistry (plural baptistries)
(Christianity) A designated space within a church, or a separate room or building associated with a church, where a baptismal font is located, and consequently, where the sacrament of Christian baptism (via aspersion or affusion) is performed.
An indoor pool used for baptism by immersion.
Source: Wiktionary
Bap"tis*ter*y,Bap"tis*try, n.; pl. Baptisteries (, -tries (. Etym:
[L. baptisterium, Gr. : cf. F. baptistère.] (Arch.)
(a) In early times, a separate building, usually polygonal, used for
baptismal services. Small churches were often changed into
baptisteries when larger churches were built near.
(b) A part of a church containing a font and used for baptismal
services.
Source: Webster’s Unabridged Dictionary 1913 Edition