An exedra adopted by James Cameron for a neoclassical interior space, at the Hermitage

In architecture an exedra is a semicircular recess, headed by a half-dome, which is usually set into a building's facade. The original Greek sense (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 conversation. An exedra may also be expressed by a curved break in a colonnade, perhaps with a semi-circular seat.

A classic example of an exedra on a (comparatively) reduced scale within its context, is the central niche of the Trevi Fountain (illus. at that entry) in Rome, sheltering a statue of Neptune. Many classicizing bandshells in public parks are exedras (exedrae is owlishly correct), for the shape, with its half-dome heading, reflects sound forwards. The Hollywood Bowl's shell (illus. at that entry) takes the form of the head of a gargantuan exedra, stripped of classicizing details.

In the 1st century CE, Nero's architects incorporated exedras throughout the planing 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 exedras 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 in hearing cases. In Byzantine architecture and Romanesque architecture this familiar feature developed into the Apse and is fully treated there.

In Muslim architecture, the exedra becomes a mihrab and invariably retains religious associations, wherever it is seen, even on the smallest scale, as a prayer niche.

Both Baroque and Neoclassical architecture used exedras, Baroque architects to enrich the play of light and shade and give rein to expressive volumes, Neoclassical architects to articulate the rhythmic pacing of a wall elevation. The interior exedra was richly exploited by Scottish neoclassical architect Robert Adam and his followers (see James Cameron's exedra illustration above, left).

External link

• LacusCurtius website: "Exedra," in Smith's Dictionary of Greek and Roman Antiquities, (1875)