BSD license

BSD licenses represent a family of permissive free software licenses. The original was used for the Berkeley Software Distribution (BSD), a Unix-like operating system after which the license is named. The original owners of BSD were the Regents of the University of California because BSD was first written at the University of California, Berkeley. The first version of the license was revised, and the resulting licenses are more properly called modified BSD licenses. Permissive licenses, sometimes with important differences pertaining to license compatibility, are referred to as "BSD-style licenses". Several BSD-like licenses, including the New BSD license, have been vetted by the Open Source Initiative as meeting their definition of open source.

The licenses have few restrictions compared to other free software licenses such as the GNU General Public License or even the default restrictions provided by copyright, putting it relatively closer to the public domain.

The BSD License allows proprietary use, and for the software released under the license to be incorporated into proprietary products. Works based on the material may be released under a proprietary license or as closed source software. This is the reason for widespread use of the BSD code in proprietary products, ranging from Juniper Networks routers to Mac OS X.

It is possible for something to be distributed with the BSD License and some other license to apply as well. This was in fact the case with very early versions of BSD itself, which included proprietary material from AT&T.