General Public License (GPL)
The GNU General Public License or GPL is used by almost all GNU software, and more than half of all FreeSoftware. Currently the GPL v3 (released in 2007) is the most widely used one, followed by GPL v.2.
It's a DFSG compatible license.
You can get a verbatim copy :
The other DFSG Licenses.
http://www.gnu.org/licenses/licenses.html#GPL GNU's page about GPL Licenses