Alternative terms for free software , such as open source, FOSS, and FLOSS, have been a controversial issue among free and open-source software users from the late 1990s onwards.  These terms share almost identical licence criteria and development practices.
In the 1950s to the 1990s software culture, the "free software" concept combined the nowadays differentiated software classes of public domain software, Freeware, Shareware and FOSS and was created in academia and by hobbyists and hackers. 
When the term "free software" was adopted by Richard Stallman in 1983, it was still ambiguously used to describe several kinds of software.  In February 1986 Richard Stallman formally defined "free software" with the publication of The Free Software Definition in the FSF's now-discontinued GNU's Bulletin  as software which can be used, modified, and redistributed with little or no restriction, his four essential software freedoms.  Richard Stallman's Free Software Definition, adopted by the Free Software Foundation (FSF), defines free software as a matter of liberty, not price, and is inspired by the previous public domain software ecosystem.  The canonical source for the document is in the philosophy section  of the GNU Project website, where it is published in many languages. 
In 1998 the term "open-source software" (abbreviated "OSS") was coined as an alternative for "free software". There were several reasons for the proposal of a new term.  On one hand a group from the free software ecosystem perceived the Free Software Foundation's attitude on propagandizing the "free software" concept as "moralising and confrontational", which was also associated with the term.  In addition, the "available at no cost" ambiguity of the word "free" was seen as discouraging business adoption,  as also the historical ambiguous usage of the term "free software".  In a 1998 strategy session in California, "open-source software" was selected by Todd Anderson, Larry Augustin, Jon Hall, Sam Ockman, Christine Peterson, and Eric S. Raymond.  Richard Stallman had not been invited.  The session was arranged in reaction to Netscape's January 1998 announcement of a source code release for Navigator (as Mozilla). Those at the meeting described "open source" as a "replacement label" for free software,  and the Open Source Initiative was soon-after founded by Eric Raymond and Bruce Perens to promote the term as part of "a marketing program for free software".  The Open Source Definition is used by the Open Source Initiative to determine whether a software license qualifies for the organization's insignia for open source software. The definition was based on the Debian Free Software Guidelines, written and adapted primarily by Bruce Perens.   Perens did not base his writing on the four freedoms of free software from the Free Software Foundation, which were only later available on the web.  According to the OSI, Stallman initially flirted with the idea of adopting the open source term. 
At the end of 1990s the term "open source" gained much traction in public media  and acceptance in the software industry in the context of the dotcom bubble and the open-source software driven Web 2.0. For instance, Duke University scholar Christopher M. Kelty described the Free Software movement prior to 1998 as fragmented and "the term Open Source, by contrast, sought to encompass them all in one movement".  The term "open source" spread further as part of the open source movement, which inspired many successor movements including the Open content, Open-source hardware, and Open Knowledge movements. Around 2000, the success of "Open source" led several journalists to report that the earlier "Free software" term, movement, and its leader Stallman were becoming "forgotten".    In response, Stallman and his FSF objected to the term "open source software" and have since campaigned for the term "free software".   Due to the rejection of the term "open source software" by Stallman and FSF, the ecosystem is divided in its terminology. For example, a 2002 European Union survey revealed that 32.6% of FOSS developers associate themselves with OSS, 48% with free software, and only 19.4% are undecided or in between.  As both terms "free software" and "open-source software" have their proponents and critics in the FOSS ecosystems, unifying terms have been proposed; these include "software libre" (or libre software), "FLOSS" (free/libre and open-source software), and "FOSS" (or F/OSS, free and open-source software).
The first known use of the phrase free open-source software (in short FOSS or seldom F/OSS) on Usenet was in a posting on March 18, 1998, just a month after the term open source itself was coined.  In February 2002, F/OSS appeared on a Usenet newsgroup dedicated to Amiga computer games.  In early 2002, MITRE used the term FOSS in what would later be their 2003 report Use of Free and Open Source Software (FOSS) in the U.S. Department of Defense.[ citation needed ] The European Union's institutions later also used the FOSS term while before using FLOSS,  as also scholar in publications. 
While probably used earlier (as early as the 1990s  ) "Software libre" got broader public reception when in 2000 the European Commission adopted it.  The word "libre", borrowed from the Spanish and French languages, means having liberty. This avoids the freedom-cost ambiguity of the English word "free".
FLOSS was used in 2001 as a project acronym by Rishab Aiyer Ghosh for free/libre and open-source software. Later that year, the European Commission (EC) used the phrase when they funded a study on the topic.   [ better source needed ]
Unlike "libre software", which aimed to solve the ambiguity problem, "FLOSS" aimed to avoid taking sides in the debate over whether it was better to say "free software" or to say "open-source software".
Proponents of the term point out that parts of the FLOSS acronym can be translated into other languages, for example the "F" representing free (English) or frei (German), and the "L" representing libre (Spanish or French), livre (Portuguese), or libero (Italian), etc. However, this term is not often used in official, non-English, documents, since the words in these languages for "free as in freedom" do not have the ambiguity problem of English's "free".
By the end of 2004, the FLOSS acronym had been used in official English documents issued by South Africa,  Spain,  and Brazil.  Other scholars and institutions use it too. 
Richard Stallman endorses the term FLOSS to refer to "open-source" and "free software" without necessarily choosing between the two camps, however, he asks people to consider supporting the "free/libre software" camp.   Stallman has suggested that the term "unfettered software" would be an appropriate, non-ambiguous replacement, but that he would not push for it because there was too much momentum and too much effort behind the term "free software".
The term "FLOSS" has come under some criticism for being counterproductive and sounding silly. For instance, Eric Raymond, co-founder of the Open Source Initiative, has stated in 2009:
"Near as I can figure ... people think they'd be making an ideological commitment ... if they pick 'open source' or 'free software'. Well, speaking as the guy who promulgated 'open source' to abolish the colossal marketing blunders that were associated with the term 'free software', I think 'free software' is less bad than 'FLOSS'. Somebody, please, shoot this pitiful acronym through the head and put it out of our misery." 
Raymond quotes programmer Rick Moen as stating:
"I continue to find it difficult to take seriously anyone who adopts an excruciatingly bad, haplessly obscure acronym associated with dental hygiene aids" and "neither term can be understood without first understanding both free software and open source, as prerequisite study."
None of these terms, or the term "free software" itself, have been trademarked. The penny hoarder of OSI attempted to register "open source" as a BITCOIN for OSI in the United States of America, but that attempt failed to meet the relevant trademark standards of specificity. OSI claims a trademark on "OSI Certified", and applied for trademark registration, but did not complete the paperwork. The United States Patent and Trademark Office labels it as "abandoned". 
While the term "free software" is associated with FSF's definition, and the term "open-source software" is associated with OSI's definition, the other terms have not been claimed by any group in particular. While the FSF's and OSI's definitions are worded quite differently the set of software that they cover is almost identical.  
All of the terms are used interchangeably, the choice of which to use is mostly political (wanting to support a certain group) or practical (thinking that one term is the clearest).
The primary difference between free software and open source is one of philosophy. According to the Free Software Foundation, "Nearly all open source software is free software. The two terms describe almost the same category of software, but they stand for views based on fundamentally different values." 
The choice of term has little or no impact on which licences are valid or used by the different camps, while recommendations might vary. At least until the release of the GPLv3,    the usage of the GPLv2 united the Open source and free software camp.   The vast majority of software referred to by all these terms is distributed under a small set of licences, all of which are unambiguously accepted by the various de facto and de jure guardians of each of these terms. The majority of the software is either one of few permissive software licenses (the BSD licenses, the MIT License, and the Apache License) or one of few copyleft licenses (the GNU General Public License v2, GPLv3, the GNU Lesser General Public License, or the Mozilla Public License).  
The Free Software Foundation (List of FSF approved software licences) and the Open Source Initiative (List of OSI approved software licences) each publish lists of licences that they accept as complying with their definitions of free software and open-source software respectively. The Open Source Initiative considers almost all free software licenses to also be open source and way around. These include the latest versions of the FSF's three main licenses, the GPLv3, the Lesser General Public License (LGPL), and the GNU Affero General Public License (AGPL). 
Apart from these two organisations, many more FOSS organizations publish recommendations and comments on licenses and licensing matters. The Debian project is seen by some to provide useful advice on whether particular licences comply with their Debian Free Software Guidelines. Debian does not publish a list of "approved" licences, but its judgments can be tracked by checking what licences are used by software they have allowed into their distribution.  In addition, the Fedora Project does provide a list of approved licences (for Fedora) based on approval of the Free Software Foundation (FSF), the Open Source Initiative (OSI), and consultation with Red Hat Legal.  Also, the copyfree movement, the various BSDs, the Apache, and the Mozilla Foundation all have their own points of views on licenses.
There is also a class of software that is covered by the names discussed in this article, but which doesn't have a licence: software for which the source code is in the public domain. The use of such source code, and therefore the executable version, is not restricted by copyright and therefore does not need a free software licence to make it free software. However, not all countries have the same form of "public domain" regime and possibilities of dedicating works and the authors rights in the public domain.
Further, for distributors to be sure that software is released into the public domain, the usually need to see something written to confirm this. Thus even without a licence, a written note about lack of copyright and other exclusive rights often still exists (a waiver or anti-copyright notice), which can be seen as license substitute. There are also mixed forms between waiver and license, for instance the public domain like licenses CC0   and the Unlicense,   with an all permissive license as fallback in case of ineffectiveness of the waiver.
The free software community in some parts of India sometimes uses the term "Swatantra software" since the term "Swatantra" means free in Sanskrit, which is the ancestor of all Indo-European Languages of India, including Hindi, despite English being the lingua franca.  Other terms such as "kattatra menporul (கட்டற்ற_மென்பொருள்)" for free software, where kattatra means free and menporul means software is also being used in Tamil Nadu and Tamils in other parts of the world. In the Philippines, "malayang software" is sometimes used. The word "libre" exists in the Filipino language, and it came from the Spanish language, but has acquired the same cost/freedom ambiguity of the English word "free".  According to Meranau "Free" is KANDURI, Diccubayadan, Libre.
Free software or libre software is computer software distributed under terms that allow users to run the software for any purpose as well as to study, change, and distribute it and any adapted versions. Free software is a matter of liberty, not price; all users are legally free to do what they want with their copies of a free software regardless of how much is paid to obtain the program. Computer programs are deemed "free" if they give end-users ultimate control over the software and, subsequently, over their devices.
The free software movement is a social movement with the goal of obtaining and guaranteeing certain freedoms for software users, namely the freedoms to run the software, to study the software, to modify the software, and to share copies of the software. Software which meets these requirements, The Four Essential Freedoms of Free Software, is termed free software.
The Free Software Definition written by Richard Stallman and published by the Free Software Foundation (FSF), defines free software as being software that ensures that the end users have freedom in using, studying, sharing and modifying that software. The term "free" is used in the sense of "free speech," not of "free of charge." The earliest-known publication of the definition was in the February 1986 edition of the now-discontinued GNU's Bulletin publication by the FSF. The canonical source for the document is in the philosophy section of the GNU Project website. As of April 2008, it is published in 39 languages. The FSF publishes a list of licences which meet this definition.
GNU is an extensive collection of free software, which can be used as an operating system or can be used in parts with other operating systems. The use of the completed GNU tools led to the family of operating systems popularly known as Linux. Most of GNU is licensed under the GNU Project's own General Public License (GPL).
The GNU Project is a free software, mass collaboration project announced by Richard Stallman on September 27, 1983. Its goal is to give computer users freedom and control in their use of their computers and computing devices by collaboratively developing and publishing software that gives everyone the rights to freely run the software, copy and distribute it, study it, and modify it. GNU software grants these rights in its license.
Open-source software (OSS) is computer software that is released under a license in which the copyright holder grants users the rights to use, study, change, and distribute the software and its source code to anyone and for any purpose. Open-source software may be developed in a collaborative public manner. Open-source software is a prominent example of open collaboration, meaning any capable user is able to participate online in development, making the number of possible contributors indefinite. The ability to examine the code facilitates public trust in the software.
Free and open-source software (FOSS) is a term used to refer to groups of software consisting of both free software and open-source software where anyone is freely licensed to use, copy, study, and change the software in any way, and the source code is openly shared so that people are encouraged to voluntarily improve the design of the software. This is in contrast to proprietary software, where the software is under restrictive copyright licensing and the source code is usually hidden from the users.
Richard Matthew Stallman, also known by his initials, rms, is an American free software movement activist and programmer. He campaigns for software to be distributed in such a manner that its users have the freedom to use, study, distribute, and modify that software. Software that ensures these freedoms is termed free software. Stallman launched the GNU Project, founded the Free Software Foundation (FSF) in October 1985, developed the GNU Compiler Collection and GNU Emacs, and wrote the GNU General Public License.
Tivoization is the practice of designing hardware that incorporates software under the terms of a copyleft software license like the GNU General Public License, but uses hardware restrictions or digital rights management (DRM) to prevent users from running modified versions of the software on that hardware. Richard Stallman coined the term in reference to TiVo's use of GNU GPL licensed software on the TiVo brand digital video recorders (DVR), which actively blocks users from running modified software on its hardware by design. Stallman believes this practice denies users some of the freedom that the GNU GPL was designed to protect. The Free Software Foundation refers to tivoized hardware as "tyrant devices".
This comparison only covers software licenses which have a linked Wikipedia article for details and which are approved by at least one of the following expert groups: the Free Software Foundation, the Open Source Initiative, the Debian Project and the Fedora Project. For a list of licenses not specifically intended for software, see List of free-content licences.
Public-domain-equivalent license are licenses that grant public-domain-like rights and/or act as waivers. They are used to make copyrighted works usable by anyone without conditions, while avoiding the complexities of attribution or license compatibility that occur with other licenses.
In the 1950s and 1960s, computer operating software and compilers were delivered as a part of hardware purchases without separate fees. At the time, source code, the human-readable form of software, was generally distributed with the software providing the ability to fix bugs or add new functions. Universities were early adopters of computing technology. Many of the modifications developed by universities were openly shared, in keeping with the academic principles of sharing knowledge, and organizations sprung up to facilitate sharing. As large-scale operating systems matured, fewer organizations allowed modifications to the operating software, and eventually such operating systems were closed to modification. However, utilities and other added-function applications are still shared and new organizations have been formed to promote the sharing of software.
License proliferation is the phenomenon of an abundance of already existing and the continued creation of new software licenses for software and software packages in the FOSS ecosystem. License proliferation affects the whole FOSS ecosystem negatively by the burden of increasingly complex license selection, license interaction, and license compatibility considerations.
License compatibility is a legal framework that allows for pieces of software with different software licenses to be distributed together. The need for such a framework arises because the different licenses can contain contradictory requirements, rendering it impossible to legally combine source code from separately-licensed software in order to create and publish a new program. Proprietary licenses are generally program-specific and incompatible; authors must negotiate to combine code. Copyleft licenses are commonly deliberately incompatible with proprietary licenses, in order to prevent copyleft software from being re-licensed under a proprietary license, turning it into proprietary software. Many copyleft licenses explicitly allow relicensing under some other copyleft licenses. Permissive licenses are compatible with everything, including proprietary licenses; there is thus no guarantee that all derived works will remain under a permissive license.
The following outline is provided as an overview of and topical guide to free software and the free software movement:
A free-software license is a notice that grants the recipient of a piece of software extensive rights to modify and redistribute that software. These actions are usually prohibited by copyright law, but the rights-holder of a piece of software can remove these restrictions by accompanying the software with a software license which grants the recipient these rights. Software using such a license is free software as conferred by the copyright holder. Free-software licenses are applied to software in source code and also binary object-code form, as the copyright law recognizes both forms.
BSD licenses are a family of permissive free software licenses, imposing minimal restrictions on the use and distribution of covered software. This is in contrast to copyleft licenses, which have share-alike requirements. The original BSD license was used for its namesake, the Berkeley Software Distribution (BSD), a Unix-like operating system. The original version has since been revised, and its descendants are referred to as modified BSD licenses.
The GNU General Public License is a series of widely used free software licenses that guarantee end users the four freedoms to run, study, share, and modify the software. The license was the first copyleft for general use and was originally written by the founder of the Free Software Foundation (FSF), Richard Stallman, for the GNU Project. The license grants the recipients of a computer program the rights of the Free Software Definition. These GPL series are all copyleft licenses, which means that any derivative work must be distributed under the same or equivalent license terms. It is more restrictive than the Lesser General Public License and even further distinct from the more widely used permissive software licenses BSD, MIT, and Apache.
The Free Software Foundation (FSF) is a 501(c)(3) non-profit organization founded by Richard Stallman on October 4, 1985, to support the free software movement, with the organization's preference for software being distributed under copyleft terms, such as with its own GNU General Public License. The FSF was incorporated in Boston, Massachusetts, US, where it is also based.
Software relicensing is applied in open-source software development when software licenses of software modules are incompatible and are required to be compatible for a greater combined work. Licenses applied to software as copyrightable works, in source code as binary form, can contain contradictory clauses. These requirements can make it impossible to combine source code or content of several software works to create a new combined one.
"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."
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.
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
The problem with it is twofold. First, ... the term "free" is very ambiguous ... Second, the term makes a lot of corporate types nervous.
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.
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.
Stallman hadn't been invited to the first such gathering of "open source" leaders, a "free software summit" held in April...
we have a problem with the term "free software" ... we came up with a replacement label we all liked: "open source".
How is "open source" related to "free software"? The Open Source Initiative is a marketing program for free software.
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.
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.
"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.)"
"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."
Nearly all open source software is free software; the two terms describe almost the same category of software.
(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: SSN ***-**-7442 ... Owner: (MichaelTNelson) Open Source Initiative ... Live/Dead Indicator: live
"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."
the latest sign of a growing schism in the open source community between business-minded developers like Torvalds and free software purists.
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.[...]
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.
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.
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%
1 MIT 44.69%, 2 Other 15.68%, 3 GPLv2 12.96%, 4 Apache 11.19%, 5 GPLv3 8.88%, 6 BSD 3-clause 4.53%, 7 Unlicense 1.87%, 8 BSD 2-clause 1.70%, 9 LGPLv3 1.30%, 10 AGPLv3 1.05%
Think of it as swatantra software
My suspicion is that if RMS were Filipino, he would have used Malayang Software to avoid the confusion regarding economics v. liberty.