barrel-vault
vaulted, semi-cylindrical construction used often as roof.

caldarium
Derivative of the Latin verb caleo (= warm up). It is the strongly heated room of Roman baths. Its hot plunge pool was used to take not only a hot bath but also a steam bath due to high levels of humidity. It was also called the "inner room".

cross- (groin-) vault
A vault formed over square or rectangular spaces by the interpenetration of two barrel-vaults of equal hight and diameter. The lines of the intersection form a diagonal cross.

frigidarium
A large cold pool to drop into after enjoying a hot Roman bath (from frigeo). Normally frigidarium has used after a visit to warm rooms (caldarium) or after a training in palaistra. As the largest room in the thermae and often functioned as a hall for social events or communication

gymnasium
The gymnasium was one of the most important centres of public life in Greek cities. The institution of the gymnasium, directly connected with the development of the Greek city, aimed to create virtuous citizens and gallant warriors. As educational institutions of public character, the gymnasia were intended for the physical and theoretical education of the young and consisted of separate spaces for special purposes.

hypocaust, the
the main system for the heating of ancient baths. The word means literally a “furnace that burns underneath”. With this system the room’s floor was supported by small poles and the space underneath the floor was heated by the circulation of hot air, while the heat was transferred through the walls by conductors.

tepidarium
The word is derived from the verb tepeo meaning ‘to be tepid’. It is the room of tepid water in the Roman thermae. It was also called middle house or tepid house and was usually situated between the caldarium and the frigidarium. Its main function was the acclimatization of the bather to the change of temperature. Being at the Tepidarium the visitor could also apply ointments on his/her body before or after the hot bath, although, there was a special room for this function called unctorium.