my high-level definition of sauna is:
a sauna is an unnaturally hot space where one bathes or relaxes, characterized by its ability to produce löyly
necessary elements: an enclosed space, a heat source, rocks, water
[ more detail on that definition here ]
that definition is of sauna, the hot space. to be more precise, a sauna space consists of two spaces: the hot space and the lounge space.
- the hot space is where löyly is produced. usually this is a room constructed from wood paneling, timbers, or logs, although rooms of differing material, tents, underground spaces, and other spaces can be used for sauna
- the lounge space is where a sauna-goer goes after spending time in the hot room to cool down or relax. usually this is an adjacent room, porch, or patio and may be characterized by bathing features such as showers, baths, or, for the lucky, a freshwater lake
usually sauna-goers alternate several times between these spaces over the course of a sauna [ sauna, the activity ]