opus (ōˈpəs) [key] [Lat., = work], in music, term used in cataloging a composer's works, designating either a single composition or a group published together or considered a unit. Opus numbers assigned by the composer are of greater value than those assigned by the publisher. Beethoven was the first composer whose use of opus numbers was consistent enough to be of value.
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.
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