EXEDRA, a term originally describing any outdoor seat or recess. Because such seats were usually semicircular, in modern architectural usage the term has come to signify any semicircular seat or recess, however large, indoors or out. In the Roman baths they were of large size and like apses were covered with a hemi spherical vault. An example 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 as places leading out of porticoes, where philosophers and rhetoricians could debate or harangue. The term is differentiated from apse (q.v.) by the fact that an apse is usually at the end of an aisle or building, and designed to enshrine an altar, tomb or statue, whereas an exedra may be in any location and without such definite purpose.