A software license from the Free Software Foundation (FSF) that ensures every user receives the essential freedoms that define "free" software, which is free of restrictions (see free software). Also called "GPL" and "GNU GPL," it was created to distribute the software of the GNU operating system (see GNU). Approximately 70% of free software packages are released under this license, including most GNU programs and thousands of others. The GNU General Public License is also considered an open source license (see open source).|
Copyleft, Not Copyright
The license embodies the Free Software Foundation's "copyleft" rule, which means that anyone is allowed to make changes or extend the source code and redistribute it as long as the changes are clearly marked, and the modified work is also licensed under the GNU General Public License.
Version 3 (GPLv3)
In 2007, Version 3 of the license was released to address several issues. It forbids Tivoization, which is the practice of designing hardware to prevent modified software from running on it (see Tivoization), and it is designed to yield results that are more uniform between countries despite variations in their copyright laws. GPLv3 also provides explicit protection to users and redistributors of a program against being sued for patent infringements by organizations connected with the program's development.
The GNU Lesser GPL (LGPL)
The GNU Lesser General Public License is meant for free software that allows linking with non-free software. It was originally called the "GNU Library GPL," but the name was changed to remove the implication that all libraries should be licensed this way. "Lesser" means the license does less to protect the user's freedom than the regular GNU GPL. See GNU Affero General Public License, free software, open source, copyright, Free Software Foundation and GNU.