the BSD license is a free software license. It's not a copyleft license, or a GNU license, but its a free software license. The 2 and 3 clause BSD licenses ar

the BSD license is a free software license. It's not a copyleft license, or a GNU license, but its a free software license. The 2 and 3 clause BSD licenses are GPL-compatible free software licenses. http://www.gnu.org/licenses/license-list.html#ModifiedBSD http://www.gnu.org/licenses/license-list.html#ModifiedBSD Even the original 4-clause BSD license is a free software license, although the 'advertising' clause is GPL-incompatible. It's also not used much any more. http://www.gnu.org/licenses/license-list.html#OriginalBSD http://www.gnu.org/licenses/license-list.html#OriginalBSD