- In ancient Greece and Rome, a roofed building for performancesof vocal and instrumental music. The term (also given as odeonand odeion) derived from the original Odeion music hall builtby Pericles in about 440 BC next to the Theatre of Dionysusin Athens. This hall was also used for musical competitions and fora preliminary ceremony held before poetry contests that included aparade of dramatists, actors, and chorus members dressed in theircostumes. A public announcement was also made of the names of theplaywrights and their works and of the names of the choregi(see choregus). In the 18th and 19th centuries thename odeum or odeon was often given to theaters and halls used formusical performances. Odeon was the tradename of a British cinemachain founded in 1933.