What is licensing?
Licensing is when a copyright owner gives permission for someone else to do something normally restricted by copyright law. For example, the creator of a song may license a song to an advertising agency, allowing the ad company to use parts of her song in a television commercial in exchange for compensation.
Sometimes a creator may want to give everybody the permission to make copies of his or her work. For example, some musicians want fans to make copies and share their songs, so they license their songs in a way that gives others explicit permission to copy and share them. One increasingly common set of licenses that exist for this purpose are Creative Commons licenses.
Find out more here: http://www.teachingcopyright.org/handout/copyright-faq