definition
strict definition
sauna
A strongly heated wooden or wood-lined room, or group of rooms, used for bathing in hot air and steam.
A sauna is a wooden room, or collection of similar rooms, where people expose themselves to high heat with varying humidity for a feeling of refreshment and well-being. They often also include facilities for cooling, so that users can alternate between heat and cold.
The heated room provides the bathing environment. Humidity varies with the sauna and its operation, including the production of steam.
Cooling facilities can accompany the heated rooms so users can alternate between them. A full sequence of separate bathing rooms is not required.