There are specific controversies; take GNU vs OSI. GNU elaborates the differences on their site: https://www.gnu.org/philosophy/free-software-for-freedom.en.htm

There are specific controversies; take GNU vs OSI. GNU elaborates the differences on their site: https://www.gnu.org/philosophy/free-software-for-freedom.en.html https://www.gnu.org/philosophy/free-software-for-freedom.en..... I couldn't find OSI's take on their website, other than a general lack of reference to GNU/FSF's idea of Free Software. Then there are disagreements on specific licenses. OSI approves licenses GNU does not classify as Free, and GNU classifies licenses as Free that OSI does not approve. Then there's GitHub, which publishes a site to help you "choose an open source license," which includes a license not approved by OSI (the Unlicense), and only makes a reference to OSI as an "additional resource". Likewise, GitHub lists FSF as an "additional resource," while consistently using the term open source, not free, and not free and open. Digital Ocean explains the difference between free and open-source software: https://www.digitalocean.com/community/tutorials/Free-vs-Open-Source-Software https://www.digitalocean.com/community/tutorials/Free-vs-Ope.... Eliah Kagan answers the question on AskUbuntu with some explanation of the history and plenty of links: https://askubuntu.com/questions/78958/is-there-a-difference-between-free-software-and-open-source-software#79316 https://askubuntu.com/questions/78958/is-there-a-difference-....