A work based on one or more preexisting works.
The owner of the copyright in the preexisting work usually has the right to prevent others from creating derivative works.
An authorized derivative work is separately "copyrightable."
Examples of derivative works include reproductions of works of art, sculptures based on drawings, maps based on previously published sources, lithographs based on paintings, sequels to movies, movies based on books or plays, etc.
In addition, editorial revisions, annotations or other modifications can be considered derivative works. This only applies if the changes as a whole are sufficient to represent an original work of authorship.
The copyright in any derivative work extends only to the new material, and not to the original underlying work.