apodyterion, -a
An undressing room, next to the entrance in a bathhouse, or a gymnasium, or a palaestra.

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".

exedra, the
1. Large semicircular niche-like structure with stone seats ranged around the walls, often outdoors or with a hemidome over. An exedra may also be expressed by a curved break in a colonnade, perhaps with a semi-circular seat.2. The rectangular hall of the palaestra, open to the courtyard with columns at the front. The exedrae in gymnasium and palaestra could have served many functions. Usually a hall of such type was the Ephebeum.

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

palaestra
A colonnaded enclosure for athletic exercise. The palaestra functioned both independently and as a part of the Greek gymnasium. It was formed as an open court surrounded by colonnades with adjoining rooms.

pillar
Pier of square or rectangular cross-section.

propylon
Monumental architectural entrance, most often to a sanctuary or a building complex.

stoa, portico, the
A long building with a roof supported by one or two colonnades parallel to its back wall.

sudatorium
It is the architectural term, deriving from the latin verb "sudo" (=sweat), for the sweating room of the roman baths. It is usually a vaulted room of rectangular form between the caldarium and the tepidarium. In the Early Roman times (1st- 2nd c. B.C.) sudatoria used to be of circular form.

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.