Definition of orchestra

• n. - The space in a theater between the stage and the audience; -- originally appropriated by the Greeks to the chorus and its evolutions, afterward by the Romans to persons of distinction, and by the moderns to a band of instrumental musicians.
• n. - The place in any public hall appropriated to a band of instrumental musicians.
• n. - Loosely: A band of instrumental musicians performing in a theater, concert hall, or other place of public amusement.
• n. - Strictly: A band suitable for the performance of symphonies, overtures, etc., as well as for the accompaniment of operas, oratorios, cantatas, masses, and the like, or of vocal and instrumental solos.
• n. - A band composed, for the largest part, of players of the various viol instruments, many of each kind, together with a proper complement of wind instruments of wood and brass; -- as distinguished from a military or street band of players on wind instruments, and from an assemblage of solo players for the rendering of concerted pieces, such as septets, octets, and the like.
• n. - The instruments employed by a full band, collectively; as, an orchestra of forty stringed instruments, with proper complement of wind instruments.