From Fedora Project Wiki

Proprietary :: Programs which are only distributed in binary form are often referred to as "proprietary" or "closed source" programs. Some proprietary products are provided free of charge, but only to those who agree to the restrictions included in the user license. The licensing terms and availability of source code differentiate proprietary software from "commercial" software. Proprietary software may also have patent or copyright restrictions attached that further reduce the freedom of users to study, copy, or modify the software.