Copyright, licenses

Copyright is a set of exclusive rights (with exceptions) granted to the authors of creative works (literary or musical works, movies, sound recordings, paintings, photographs or software, ...).
These rights to use, perform, reproduce, sell or adapt the work are granted to the authors for a limited time after which the work passes into the public domain.

The holder of a copyright can require that a license be accepted as a condition of being allowed to use, reproduce, or modify the licensed work.

A software license defines the authorised uses The use of a software program which has not yet passed into the public domain is therefore restricted to the uses authorized by its license.