1) Ancient Roman bath 2) Hot room in a bath-suite 
Laconicum (i.e. Spartan, sc. balneum, bath), the dry sweating room of the Roman thermae, contiguous to the caldarium or hot room. The name was given to it as being the only form of warm bath that the Spartans admitted. The laconicum was usually a circular room with niches in the axes of the diagonals and was covered by a conical roof with a circul...
sauna
laconicum The sweating-room in the bath, so called from having been first used by the Spartans.
hot room (dry heat) in a bath-suite
Sweat room