Quick Answer: A license or licence is an official permission or permit to do, use, or own something. A license is granted by a party to another party as an element of an agreement between those parties. In the case of a license issued by a government, the license is obtained by applying for it. In the case of a private party, it is by a specific agreement, usually in writing. The simplest definition is "A license is a promise not to sue", because a license usually either permits the licensed party to engage in an illegal activity, and subject to prosecution, without the license, or it permits the licensed party to do something that would violate the rights of the licensing party, which, without the license, the licensed party could be sued, civilly, criminally, or both. In particular, a license may be issued by authorities, to allow an activity that would otherwise be forbidden. It may require paying a fee or proving a capability.