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 terracotta flue pipes of rectangular section, placed side by side, through which hot air and smoke from the suspensura passed to an exit in the roof.
When Arabs and Turks overran the Eastern Roman Empire, they adopted and developed this feature in their baths or hammams.
This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). "Sudatorium". Encyclopædia Britannica. 26 (11th ed.). Cambridge University Press. p. 19.