Copyright Transfer Agreement vs. License
If the author as the copyright owner transfers all or some of his rights (with or without particular conditions), it is generally termed an "assignment".
A "license" means that the copyright remains with the author (the licensor), who grants the (or some of the) rights of use to the licensee.
An exclusive license exists when the rights of use can be exercised only by one particular licensee.
If the licensor can allow other licensees to exercise the same rights of use, the license is non-exclusive.
Whether the licensor himself keeps the (or some of the) rights of use depends on the particular agreement; if this is the case, the license sometimes is called "sole license".
(Definition provided by Reto Hilty, MPI for Intellectual Property, Competition and Tax Law, Munich)
Last changed: 16 October 2003