&gt; might use lowercase-f &quot;free&quot; to refer to open source licenses in general<p>That&#x27;s because &quot;free&quot; and &quot;open source&quot; are <i>exactly the same thing</i>. They refer to the exact same set of licenses and software (within epsilon of each other). &quot;Open source&quot; is a term coined in 1998 as a synonym for &quot;free software&quot;:<p><a href="http:&#x2F;&#x2F;jordi.inversethought.com&#x2F;blog&#x2F;5-things-we-have-forgotten-about-open-source&#x2F;" rel="nofollow">http:&#x2F;&#x2F;jordi.inversethought.com&#x2F;blog&#x2F;5-things-we-have-forgot...</a><p>When rms is talking about copyleft, he&#x27;s not saying it&#x27;s identical to free software. Copyleft is just a tool he advocates in order to promote free software, but it&#x27;s not a goal in itself, nor a requirement for software to be free.