The term thermae was the word the Ancient Romans used for the buildings housing their public baths.
Most Roman cities had at least one, if not many, such buildings, which were centers of public bathing and socialization.
Within the building the baths were divided according to gender. Each gender had three pools: A hot one, a lukewarm one and a cool one. They were called the caldarium, the tepidarium and the frigidarium. Sometimes there was also a steam bath: The sudatorium.
The most noteworthy ruins of a thermae are the Baths of Caracalla in Rome.