orchestra

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. Music A large group of musicians who play together on various instruments, usually including strings, woodwinds, brass instruments, and percussion instruments.
2. n. Music The instruments played by such a group.
3. n. The area in a theater or concert hall where the musicians sit, immediately in front of and below the stage.
4. n. The front section of seats nearest the stage in a theater.
5. n. The entire main floor of a theater.
6. n. A semicircular space in front of the stage used by the chorus in ancient Greek theaters.

Century Dictionary and Cyclopedia

1. n. The part of a theater or other public place appropriated to the musicians. In theaters, in classic times, the orchestra was a circular or semicircular level space lying between the rising tiers of seats of the auditorium and the stage. In Greek theaters this space was circular, and was allotted to the chorus, which performed its evolutions about the thymele or altar of Dionysus, which occupied the center of the orchestra. Among the Romans the orchestra corresponded nearly to the orchestra of modern play-houses, and was set apart for the seats of senators and other persons of distinction. See diagram under diazoma.
2. n. In modern music, a company of performers on such instruments as are used in concerted music; a band. ; . (In the United States band usually signifies a military band; but in England band is interchangeable with orchestra.) The historic development of the orchestra as now known did not begin until about 1600, when the independent value of instrumental music was first generally accepted. Up to that time, though many instruments had been known and used, both alone and as supports for vocal music, they had not been systematically combined, nor had concerted music been written for them. The process of experiment, selection, and improvement in construction and mutual adaptation went on steadily until nearly 1800, when the orchestra first arrived at its present proportions. The instruments now used consist of four main groups: the strings, including violins (first and second), violas, violoncellos, and bass viols, these together constituting the largest and decidedly the most important group, which is often used entirely alone, and is then called the string-orchestra
3. n. In the early New England churches, the choir-gallery at the end opposite the pulpit: so called because in it were stationed the instrumentalists by whom the singing was accompanied.

Wiktionary

1. n. music A large group of musicians who play together on various instruments, usually including some from strings, woodwind, brass and/or percussion; the instruments played by such a group.
2. n. A semicircular space in front of the stage used by the chorus in Ancient Greek and Hellenistic theatres.
3. n. The area in a theatre or concert hall where the musicians sit, immediately in front of and below the stage, sometimes (also) used by other performers.

GNU Webster's 1913

1. 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. Now commonly called orchestra pit, to distinguish it from the section of the main floor occupied by spectators.
2. n. The space in the main floor of a theater in which the audience sits; also, the forward spectator section of the main floor, in distinction from the parterre, which is the rear section of the main floor.
3. n. The place in any public hall appropriated to a band of instrumental musicians.
4. n. Loosely: A band of instrumental musicians performing in a theater, concert hall, or other place of public amusement.
5. 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.
6. 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.
7. n. (Mus.) The instruments employed by a full band, collectively.

WordNet 3.0

1. n. seating on the main floor in a theater
2. n. a musical organization consisting of a group of instrumentalists including string players