Library General Public License
, also known as the Lesser General Public License.
This is a license commonly used with GNU projects such as GNOME on things like libraries. Software using this license is DFSG-free.
The LGPL permits you to link the libraries to "non-free" software without forcing that software to be released under the GPL or LGPL.
As is common with most canned licences, the LGPL uses terminology more appropriate for a program written in C than one written in Lisp. The AllegroServe project have written a
preamble to the LGPL that clarifies the terms for use with Lisp programs - this is often referred to as the LLGPL.
For more details see GNU Library General Public License.