EXEDRA, or Exhedra (from Gr., out, and , a seat), an architectural term originally applied to a seat or recess out of doors, intended for conversation. Such recesses were generally semicircular, as in the important example built by Herodes Atticus at Olympia. In the great Roman thermae (baths) they were of large size, and like apses were covered with a hemispherical vault. An example of these exists at Pompeii in the Street of the Tombs. From Vitruvius we learn that they were often covered over, and they are described by him (v. 11) as places leading out of porticoes, where philosophers and rhetoricians could debate or harangue.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)