A definition a license
A license grants the licensee permission, consent or clearance to use the copyrighted work according to the terms specified by the licensor, who is the owner of the copyright.
Licenses may be (1) Exclusive, (2) Sole or (3) Non-exclusive .
An exclusive license grants the licensee the power to exercise the copyright to the exclusion of all others – including the licensor. If the term of this agreement is long, the license becomes very close to an assignment of copyright.