1) Ancient Roman bath 2) Hot room in a bath-suite 3) Spot for a Turkish bath 
In architecture, a sudatorium is a vaulted sweating-room (sudor, sweat) of the Roman baths or thermae. The Roman architectural writer Vitruvius (v. 2) refers to it as concamerata sudatio. In order to obtain the great heat required, the whole wall was lined with vertical terra-cotta flue pipes of rectangular section, placed side by side, through wh...
• (n.) A sudatory.
An optional sweat-bath (humid). 
Su`da·to'ri·um noun ; plural Sudatoria . [ Latin ] A sudatory. Dunglison. 
sudatorium 1. A room, especially in an ancient Roman bathhouse, in which people are made to sweat by hot air or steam. 2. A hot-air room used for sweat baths.
hot room (dry heat) in a bath-suite
sudatory noun a bathhouse for hot air baths or steam baths
Humid sweat-bath
a hot-air bath for inducing sweating.