Editing Gnuplot (section)

== Distribution terms ==
{{Infobox software license
| name            = gnuplot License
| image           = 
| caption         =
| author          = Thomas Williams, Colin Kelley
| version         = 
| publisher       = 
| date            = 1986 – 1993, 1998, 2004
| spdx            = gnuplot<ref name="spdx">{{cite web|url=https://spdx.org/licenses/gnuplot.html|title=gnuplot License|website=Spdx.org}}</ref>
| OSI approved    = Yes
| Debian approved = Yes
| FSF approved    = Yes
| GPL compatible  = No<ref name="gnulicense">{{cite web | url=https://directory.fsf.org/wiki/License:Gnuplot | title=License:Gnuplot | publisher=Free Software Foundation | access-date=2018-11-19}}</ref>
| copyleft        = No
| linking         = 
| website         = https://sourceforge.net/p/gnuplot/gnuplot-main/ci/master/tree/Copyright
}}

Despite gnuplot's name, it is not named after, part of or related to the [[GNU Project]], nor does it use the [[GNU General Public License]]. It was named as part of a compromise by the original authors, punning on ''[[gnu]]'' (the animal) and ''newplot'' (a planned name that was discarded due to already being used).<ref name="gnuplot faq">{{cite web | url=http://www.gnuplot.info/faq/faq.html#x1-70001.2 | title=1.2 How did it come about and why is it called gnuplot? | website=Gnuplot.info | access-date=2015-02-21}}</ref>

Official source code to gnuplot is freely redistributable, but modified versions thereof are not. The gnuplot license allows instead distribution of patches against official releases, optionally accompanied by officially released source code. Binaries may be distributed along with the unmodified source code and any patches applied thereto. Contact information must be supplied with derived works for [[technical support]] for the modified software.<ref name=lice>{{Cite web|url=https://sourceforge.net/p/gnuplot/gnuplot-main/ci/master/tree/Copyright|title=gnuplot : gnuplot-main : [bcc809] : Copyright|website=Sourceforge.net|access-date=27 June 2022}}</ref>

<blockquote>
Permission to modify the software is granted, but not the right to distribute the complete modified source code. Modifications are to be distributed as patches to the released version.
</blockquote>

Despite this restriction, gnuplot is accepted and used by many [[GNU packages]] and is widely included in [[Linux distributions]] including the stricter ones such as [[Debian]] and [[Fedora (operating system)|Fedora]]. The [[Open-source software#The Open Source Definition|OSI Open Source Definition]] and the [[Debian Free Software Guidelines]] specifically allow for restrictions on distribution of modified source code, given explicit permission to distribute both patches and source code.

Newer gnuplot modules (e.g. Qt, wxWidgets, and cairo drivers) have been contributed under dual-licensing terms, e.g. gnuplot + BSD or gnuplot + GPL.