sweathouse

[ swet-hous ]
/ ˈswɛtˌhaʊs /

noun, plural sweat·hous·es [swet-hou-ziz] /ˈswɛtˌhaʊ zɪz/.

(especially among North American Indians) a special building used for cleansing and purifying one's body by sweating, in which heated water is poured over heated stones to produce steam.
Also called sweat lodge.

British Dictionary definitions for sweat lodge

sweat lodge

noun

(among native North American peoples) a structure in which water is poured onto hot stones to make the occupants sweat for religious or medicinal purposes