前述の背景があり、「Free and open-source software（自由かつオープンソースのソフトウェア）」（略してFOSS、稀にF/OSS）という用語が使われることもある。2002 年 2 月には、「F/OSS」という用語が Amigaコンピュータゲーム専用の Usenet ニュースグループにて使われている[28]。また、2002 年初頭、MITRE（英語版） は、後に 2003 年の報告書『Use of Free and Open-Source Software (FOSS) in the U.S. Department of Defense（米国国防総省における自由かつオープンソースのソフトウェア (FOSS) の使用）』の中で FOSS という用語を使用した[29] 。欧州連合の機関も、後に FLOSS を使用する前に FOSS という用語を使用しており[30] 、研究者も出版物で使用している[31]。
Software libre、Libre Software、Libreware
「Software libre」という言葉は、おそらくもっと以前（1990年代初頭）から使われていたが[32]、1999年に欧州委員会が『working group on libre software』を結成した際に、より広く一般に受け入れられるようになった[33][34]。スペイン語とフランス語から借用された「libre」という言葉は、「自由」を意味する。これにより、英語の「free」という単語の「自由」と「無償」の曖昧さが回避される。
FLOSSという語は、2001年にリシャブ・アイエル・ゴーシュ（英語版）によって「free/libre and open-source software」の頭字語として使用された。その年の後半、欧州委員会（EC）は、このトピックに関する研究に資金を提供する際にこのフレーズを使用している[35][36][より良い情報源が必要]。
^ abFree/Libre and Open Source Software: Survey and Study FLOSS Deliverable D18: FINAL REPORT – Part IV: Survey of Developers by Rishab Aiyer Ghosh et al "According to this ongoing discussion, one would expect a sharp polarization of the whole community of developers of non-proprietary software into two very different parties, one of Open Source developers and one of Free Software developers. However, figure 39 shows that, although there is clear evidence of these parties, still a share of almost one fifth of the whole sample does not care anyway if they belong to the one or to the other party." (2002)
^ abShea, Tom (1983年6月23日). “Free software – Free software is a junkyard of software spare parts”. InfoWorld. 2019年10月13日閲覧。 “"In contrast to commercial software is a large and growing body of free software that exists in the public domain. Public-domain software is written by microcomputer hobbyists (also known as "hackers") many of whom are professional programmers in their work life."”
^Karl Fogel (2016年). “Producing Open Source Software – How to Run a Successful Free Software Project”. O'Reilly Media. 2016年4月11日閲覧。 “But the problem went deeper than that. The word "free" carried with it an inescapable moral connotation: if freedom was an end in itself, it didn't matter whether free software also happened to be better, or more profitable for certain businesses in certain circumstances. Those were merely pleasant side effects of a motive that was, at its root, neither technical nor mercantile, but moral. Furthermore, the "free as in freedom" position forced a glaring inconsistency on corporations who wanted to support particular free programs in one aspect of their business, but continue marketing proprietary software in others.”
^OSI. “History of OSI”. 2025年1月30日閲覧。 “"conferees decided it was time to dump the moralizing and confrontational attitude that had been associated with "free software" in the past and sell the idea strictly on the same pragmatic, business-case grounds"”
^“Goodbye, "free software"; hello, "open source"”. 2025年1月30日閲覧。 “The problem with it is twofold. First, ... the term "free" is very ambiguous ... Second, the term makes a lot of corporate types nervous.”
^ abKelty, Christpher M. (2008年). “The Cultural Significance of free Software – Two Bits”. Duke University press – durham and london. pp. 99. 2025年1月30日閲覧。 “Prior to 1998, Free Software referred either to the Free Software Foundation (and the watchful, micromanaging eye of Stallman) or to one of thousands of different commercial, avocational, or university-research projects, processes, licenses, and ideologies that had a variety of names: sourceware, freeware, shareware, open software, public domain software, and so on. The term "open-source", by contrast, sought to encompass them all in one movement.”
^Michael Tiemann (2006年9月19日). “History of the OSI”. 2002年10月1日時点のオリジナルよりアーカイブ。2025年1月30日閲覧。 “The people present included Todd Anderson, Chris Peterson (of the Foresight Institute), John "maddog" Hall and Larry Augustin (both of Linux International), Sam Ockman (of the Silicon Valley Linux User's Group), Michael Tiemann, and Eric Raymond.”
^“The Saint of Free Software (page 2)”. 2008年6月12日時点のオリジナルよりアーカイブ。2025年1月30日閲覧。 “Stallman hadn't been invited to the first such gathering of "open source" leaders, a "free software summit" held in April...”
^“Frequently Asked Questions”. Open Source Initiative. 2006年4月23日時点のオリジナルよりアーカイブ。2025年1月30日閲覧。 “How is "open source" related to "free software"? The Open Source Initiative is a marketing program for free software.”
^Tiemann, Michael (2006年9月19日). “History of the OSI”. Open Source Initiative. 2002年10月1日時点のオリジナルよりアーカイブ。2008年8月23日閲覧。 “We realized that the Netscape announcement had created a precious window of time within which we might finally be able to get the corporate world to listen to what we have to teach about the superiority of an open development process. We realized it was time to dump the confrontational attitude that has been associated with "free software" in the past and sell the idea strictly on the same pragmatic, business-case grounds that motivated Netscape. We brainstormed about tactics and a new label. "Open source," contributed by Chris Peterson, was the best thing we came up with. Over the next week we worked on spreading the word. Linus Torvalds gave us an all-important imprimatur :-) the following day. Bruce Perens got involved early, offering to trademark "open source" and host this web site. Phil Hughes offered us a pulpit in Linux Journal. Richard Stallman flirted with adopting the term, then changed his mind.”
^Leander Kahney (1999年3月5日). “Linux's Forgotten Man – You have to feel for Richard Stallman.”. wired.com. 2001年6月22日時点のオリジナルよりアーカイブ。2025年1月30日閲覧。 “Like a Russian revolutionary erased from a photograph, he is being written out of history. Stallman is the originator of the free-software movement and the GNU/Linux operating system. But you wouldn't know it from reading about LinuxWorld. Linus Torvalds got all the ink. Even the name of the operating system, to which Torvalds contributed a small but essential part, acknowledges Torvalds alone: the Stallman part – the GNU before Linux – is almost always left out. It makes Stallman mad. At a press conference during the show, one unlucky journalist thoughtlessly called it Linux and got an earful for his mistake.”
^“Toronto Star: Freedom's Forgotten Prophet (Richard Stallman)”. linuxtoday.com (2000年10月10日). 2016年3月25日閲覧。 “"But if [Richard] Stallman is winning the war, he is losing the battle – for credit....Red Hat's Web site lists the major milestones in 'open source' software, beginning in the 1970s with AT&T's Unix system and jumping to Torvalds' kernel in 1991, completely bypassing Stallman. (Red Hat does, however, provide a link to the GNU Web site, but most people have no idea what it represents.)"”
^Nikolai Bezroukov (2014年11月1日). “Portraits of Open Source Pioneers – Part IV. Prophet”. 2016年3月25日閲覧。 “"And in the second part of 1998 "open source" became a standard umbrella term encompassing commercialized GPL-based software and first of all major commercial Linux distributions (Caldera, Red Hat, Slackware, Suse, etc). Still like is often is the case in religious schisms, Raymodism overtake of Stallmanism was not complete and Eric Raymond had run into his own PR problems with his unsuccessful attempt to grab an "open source" trademark, that generated a lot of resentment in the community. Later his "surprised by wealth" letter undermined his role of influential evangelist of "open source is the best economical model for the development of the software" message. He became an object of pretty nasty jokes, but that does not help RMS to restore the role of FSF."”
^“Trademark Electronic Search System (TESS)”. 2025年2月1日閲覧。 “(Direct link not possible, site search required) Word Mark: OSI CERTIFIED ... Goods and Services: (ABANDONED) IC A . US A . G & S: software licensed under open-source licenses. ... Serial Number: 76020694 ... Owner: (APPLICANT) Open Source Initiative ... Live/Dead Indicator: DEAD”
^ ab“Why "Open Source" misses the point of Free Software”. GNU.org. Free Software Foundation. 2023年4月20日閲覧。 “The terms “free software” and “open source” stand for almost the same range of programs. However, they say deeply different things about those programs, based on different values.”
^“Innovation Goes Public”. 2008年12月28日時点のオリジナルよりアーカイブ。2025年2月1日閲覧。 “(javascript slide #3) When I say "Open Source", I mean the same thing as Free Software.”
^Kerner, Sean Michael (2008年1月8日). “Torvalds Still Keen on GPLv2”. internetnews.com. 2015年2月12日閲覧。 “"In some ways, Linux was the project that really made the split clear between what the FSF is pushing which is very different from what open source and Linux has always been about, which is more of a technical superiority instead of a – this religious belief in freedom," Torvalds told Zemlin. So, the GPL Version 3 reflects the FSF's goals and the GPL Version 2 pretty closely matches what I think a license should do and so right now, Version 2 is where the kernel is."”
^Landley, Rob. “CELF 2013 Toybox talk”. landley.net. 2013年8月21日閲覧。 “GPLv3 broke "the" GPL into incompatible forks that can't share code. [...] FSF expected universal compliance, but hijacked lifeboat clause when boat wasn't sinking.[...]”
^Byfield, Bruce (2011年11月22日). “7 Reasons Why Free Software Is Losing Influence: Page 2”. Datamation.com. 2013年8月23日閲覧。 “At the time, the decision seemed sensible in the face of a deadlock. But now, GPLv2 is used for 42.5% of free software, and GPLv3 for less than 6.5%, according to Black Duck Software.”
^“Kernel developers' position on GPLv3 – The Dangers and Problems with GPLv3”. LWN.net (2006年9月15日). 2015年3月11日閲覧。 “"The current version (Discussion Draft 2) of GPLv3 on first reading fails the necessity test of section 1 on the grounds that there's no substantial and identified problem with GPLv2 that it is trying to solve. However, a deeper reading reveals several other problems with the current FSF draft: 5.1 DRM Clauses [...] 5.2 Additional Restrictions Clause [...] 5.3 Patents Provisions [...]since the FSF is proposing to shift all of its projects to GPLv3 and apply pressure to every other GPL licensed project to move, we foresee the release of GPLv3 portends the Balkanisation of the entire Open Source Universe upon which we rely."”
^“Top 20 licenses”. Black Duck Software (2015年11月19日). 2016年7月19日時点のオリジナルよりアーカイブ。2015年11月19日閲覧。 “1. MIT license 24%, 2. GNU General Public License (GPL) 2.0 23%, 3. Apache License 16%, 4. GNU General Public License (GPL) 3.0 9%, 5. BSD License 2.0 (3-clause, New or Revised) License 6%, 6. GNU Lesser General Public License (LGPL) 2.1 5%, 7. Artistic License (Perl) 4%, 8. GNU Lesser General Public License (LGPL) 3.0 2%, 9. Microsoft Public License 2%, 10. Eclipse Public License (EPL) 2%”
^“Re: Free Software, some thoughts”. 2021年2月24日時点のオリジナルよりアーカイブ。2025年2月1日閲覧。 “My suspicion is that if RMS were Filipino, he would have used Malayang Software to avoid the confusion regarding economics v. liberty.”
