A license is a form of contract whereby a rights-holder grants permission to a person or entity to make use of a copyrighted work in some way.
Licenses can be quite specific, granting permission for only one particular kind of use, and for a limited time, or they can be comprehensive. They may be open source, or restrictive. They may or may not be transferable to others. Licenses have always been part of copyright law, but have come to greater prominence recently with their extensive use in conjunction with computer software.
A license that does not refer to any particular copyrighted work, or to specific parties, but is instead presented as an example of the license in general.
The model license can then be modified according to circumstances. For example, Creative Commons, which offers six different types of license, makes model versions of each available.
A license granted to an institution, such as a library or school, rather than an individual.
An institutional license’s terms are predicated on the idea that the institution will be serving many different users, under a wide variety of circumstances, and that from a transaction costs perspective, it is far more efficient for all concerned to negotiate terms only once. For example, most, if not all, universities have institutional licensing agreements with the various collective management agencies for the performance of musical works. Many libraries, whether public or academic, have institutional subscriptions to commercial or academic databases, under which any patron of the library may access the database without having to negotiate personal access.
An individual license is a license granted to a single person.
Individual licenses can be negotiated for any sort of copyrighted work, but are probably most often seen in the software context, where before using purchased software, a user must agree to the licensing terms.
(non) Exclusive License
An exclusive license is one granted to the holder only.
If a license is exclusive, it means that no other similar license will be granted. For example, a rights-holder in the United States might grant an exclusive license to someone in Germany to be the sole distributor of the copyrighted work in Germany, or vice versa. A non-exclusive license is just the opposite. A person with such a license knows that many others may have been granted the exact same rights. For example, when a person purchases software, he knows that he is not the only one who has eben granted permission to use that software.