Lewis Short
baptistērĭum (noun N) = βαπτιστήριον: .
* A place for bathing or swimming, a vessel for bathing, Plin. Ep. 5, 6, 25; 2, 17, 11; Sid. Ep. 2, 2.
* In eccl. Lat., a baptistery, a baptismal font, Sid. Ep. 4, 15.
Charlton T. Lewis, Charles Short, A Latin Dictionary