Caldarium
（重定向自Calidarium）
![Caldarium from the Roman Baths at Bath, England. The floor has been removed to reveal the empty space where the hot air flowed through to heat the floor.](/Images/godic/202501/02/Caldarium5105.JPG")
A caldarium (also called a calidarium, cella caldaria or cella coctilium) was a room with a hot plunge bath, used in a Roman bath complex.
This was a very hot and steamy room heated by a hypocaust, an underfloor heating system. This was the hottest room in the regular sequence of bathing rooms; after the caldarium, bathers would progress back through the tepidarium to the frigidarium.