In copyright law, a derivative work is an artistic creation that includes aspects of work previously created and protected.
In the United States, "derivative work" is defined in 17 USC 101, section 101:
A "derivative work" is a work based upon one or more preexisting works, such as a translation, musical arrangement, dramatization, fictionalization, motion picture version, sound recording, art reproduction, abridgment, condensation, or any other form in which a work may be recast, transformed, or adapted. A work consisting of editorial revisions, annotations, elaborations, or other modifications which, as a whole, represent an original work of authorship, is a "derivative work".
The concept of derivative works is a logical extension of the framework of copyright protection in the United States. It prevents others from misappropriating the original work of a creator and redistributing it with "trival" changes without permission. If a derivative work is created with the permission of the original creator, the secondary creator maintains a copyright interest in only the aspects of the derivative work that are his or her original creations.
Wikipedia article (the free online encyclopedia) reproduced under the terms of the GNU (General Public License) Free Documentation License.