Exedra

In architecture, an exedra is a semicircular recess or plinth, often crowned by a semi-dome, which is sometimes set into a building's façade or is free-standing. The original Greek sense (ἐξέδρα, a seat out of doors) was applied to a room that opened onto a stoa, ringed with curved high-backed stone benches, a suitable place for a philosophical or other conversation. An exedra may also be expressed by a curved break in a colonnade, perhaps with a semicircular seat.

The exedra would typically have an apsidal podium that supported the stone running bench. The free-standing (open air) exedra, often originally supporting bronze portrait statues is a familiar type of Hellenistic structure, characteristically sited along sacred ways or in open places in sanctuaries, such as at Delos or Epidaurus; sometimes Hellenistic exedrae were built in relation to a city's agora, as at Priene. Monument architects have also used this free-standing style in modern times.

The exedra achieved particular popularity in Roman architecture during the Roman Empire. In the 1st century AD, Nero's architects incorporated exedrae throughout the planning of his Domus Aurea, enriching the volumes of the party rooms, a part of what made Nero's palace so breathtakingly pretentious to traditional Romans, for no one had ever seen domes and exedrae in a dwelling before. An exedra was normally a public feature: when rhetoricians and philosophers disputed in a Roman gymnasium it was in an exedra opening into the peristyle that they gathered. A basilica featured a large exedra at the far end from its entrance, where the magistrates sat, usually raised up several steps, in hearing cases. This was called a tribuna in Latin, and tribune is used for an area of raised floor backing onto a wall, often in an exedra.

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