Baptistery \Bap"tis*ter*y\,Baptistry \Bap"tis*try\, n.; pl.
{Baptisteries}, {Baptistries}. [L. baptisterium, Gr.
baptisth`rion: cf. F. baptist[`e]re.] (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.
[1913 Webster]