Odeon (Gr. udelov, from, song), a kind of public building used by the ancient Greeks for musical contests, and occasionally for other purposes. In its general plan it resembled the theatre, and sometimes it served as a place of rehearsal for the choruses. Hence it was smaller than the theatre, and was roofed over. The earliest was that called the Skias in Sparta, built by the Saurian architect Theodoras about 650 B. C. There was also an ancient one at Athens, in the S. E. part of the city, near the Hissus. A much larger and finer one was erected by Pericles at the base of the S. E. part of the acropolis, and in the immediate vicinity of the great theatre. It was burned at the capture of the city by Sulla, and restored by Ariobarzanes II., king of Cappadocia. Athens contained two other odeons, one of which has sometimes been confounded with the Pnyx; the other, a magnificent building, capable of containing 8,000 persons, was erected by Herodes Atticus below the S. W. part of the acropolis, where its rains are still visible. Many other cities of Greece and its colonies also had buildings of this class.

The first odeon in Rome was built by Domitian.