ensemble

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A unit or group of complementary parts that contribute to a single effect, especially.
• noun A coordinated outfit or costume.
• noun A coordinated set of furniture.
• noun A group of musicians, singers, dancers, or actors who perform together.
• noun A work for two or more vocalists or instrumentalists.
• noun The performance of such a work.

from The Century Dictionary.

• Together; all at once; simultaneously.
• In music, same as concerted: as, an ensemble passage or work.
• noun The union of parts in a whole; all the parts of anything taken together, so that each part is considered only in relation to the whole; specifically, the general effect of a work of art, piece of music, drama, etc.
• noun In music, the union of all the performers in a concerted composition, as in a chorus with full orchestral accompaniment.
• noun In mathematics, a manifold or collection of elements, discrete or continuous, finite, infinite, or superinfinite.

from the GNU version of the Collaborative International Dictionary of English.

• adverb All at once; together.
• noun The whole; all the parts taken together.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun a group of separate things that contribute to a coordinated whole
• noun a coordinated costume or outfit; a suit
• noun a group of musicians, dancers, actors, etc who perform together; e.g. the chorus of a ballet company
• noun music a piece for several instrumentalists or vocalists

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a group of musicians playing or singing together
• noun a cast other than the principals
• noun a coordinated outfit (set of clothing)
• noun an assemblage of parts or details (as in a work of art) considered as forming a whole
• noun the chorus of a ballet company