Gratis versus libre
Gratis versus libre is the distinction between two meanings of the English adjective "free"; namely, "for zero price" (gratis) and "with little or no restriction" (libre). The ambiguity of "free" can cause issues where the distinction is important, as it often is in dealing with laws concerning the use of information, such as copyright and patents.
The terms are largely used to categorise intellectual property, particularly computer programs, according to the licenses and legal restrictions that cover them, in the free software and open source communities, as well as the broader free culture movement. For example, they are used to distinguish freeware (software gratis) from free software (software libre).
Gratis in English is a colloquialism adopted from the various Romance and Germanic languages, ultimately descending from the plural ablative and dative form of the first-declension noun grātia in Latin. It means "free of charge", "at zero price", "free", in the sense that some good or service is supplied without payment, even though it may have value.
Libre (pron.: //) in English is adopted from the various Romance languages, ultimately descending from the Latin word lībere; its origin is closely related to liberty. It denotes "the state of being free", as in "liberty" or "having freedom". The Oxford English Dictionary (OED) considers libre to be obsolete, but the word has come back into limited use. Unlike gratis, libre appears in few English dictionaries, although there is no other English single-word adjective signifying "liberty" exclusively, without also meaning "at no monetary cost".
"Free beer" vs "free speech" distinction 
In software development, where the cost of mass production is relatively small, it is common for developers to make software available at no cost. One of the early and basic forms of this model is called freeware. With freeware, software is licensed free of charge for regular use: the developer does not gain any monetary compensation.
With the advent of the free software movement, license schemes were created to give developers more freedom in terms of code sharing, commonly called open source or free and open source software (called FLOSS, FOSS, or F/OSS). As the English adjective free does not distinguish between "for zero price" and "liberty", the phrases "free as in free beer" (gratis, freeware) and "free as in free speech" (libre, free software) were adopted. Many in the free software movement feel strongly about the freedom to use the software, make modifications, etc., whether or not this freely usable software is to be exchanged for money. Therefore, this distinction became important.
"Free software is a matter of liberty, not price. To understand the concept, you should think of free as in free speech, not as in free beer."
These phrases have become common, along with gratis and libre, in the software development and computer law fields for encapsulating this distinction. The distinction is similar to the distinction made in political science between negative liberty and positive liberty. Like "free beer", positive liberty promises equal access by all without cost or regard to income, of a given good (assuming the good exists). Like "free speech", negative liberty safeguards the right to use of something (in this case, speech) without regard to whether in each case there is a cost involved for this use (you still have free speech even though it costs money to acquire a newspaper).
Generalizing the "Gratis/Libre" distinction to the Open Access movement 
The original Gratis/Libre distinction concerns software (i.e., code), with which users can potentially do two kinds of things: (1) access and use it and (2) modify and re-use it. "Gratis" pertains to being able to access and use the code, without a price-barrier, and "Libre" pertains to being allowed to modify and re-use the code, without a permission barrier. The target content of the Open Access movement, however, is not software but published, peer-reviewed research journal article texts.
1. Code (text) accessibility and use. For published research articles, the case for making their text accessible free for all online (Gratis) is even stronger than it is for software code, because in the case of software, some developers may wish to give their code away for free, while others may wish to sell it, whereas in the case of published research article texts, all their authors, without exception, give them away for free: None seek or get royalties or fees from their sale. On the contrary, any access-denial to potential users means loss of potential research impact (downloads, citations) for the author's research—and researcher-authors' employment, salary, promotion and funding depends in part on the uptake and impact of their research. So whereas not all programmers may want their software to be accessible Gratis, all researchers want their articles to be accessible Gratis.
2. Code (text) modifiability and re-use. For published research articles, the case for allowing text modification and re-use is much weaker than for software code, because, unlike software, the text of a research article is not intended for modification and re-use. (In contrast, the content of research articles is and always was intended for modification and re-use: that is how research progresses.) There are no copyright barriers to modifying, developing, building upon and re-using an author's ideas and findings, once they have been published, as long as the author and published source are credited—but modifications to the published text are another matter. Apart from verbatim quotation, scholarly/scientific authors are not in general interested in allowing other authors to create "Mashups" of their texts. Researcher-authors are all happy to make their texts available for harvesting and indexing for search as well as data-mining, but not for re-use in altered form (without the permission of the author).
The formal analogy, and the generalization of the Gratis/Libre distinction from Open Software to Open access (publishing), have been made. However, because of the substantive disanalogies regarding (1) and (2) noted above, the analogy needs to be treated with some caution.
See also 
- Alternative terms for free software
- Free software community
- Libre knowledge
- List of FSF approved software licences
- List of open source licenses
- Lessig, Lawrence (September 2006). "Free, as in beer". Wired. Retrieved 2009-03-18.
- OED.com, OED definition of libre: "Obs. Of the will: Free". Access to the OED is libre, but not gratis.
- The Onelook dictionary website finds about 5 monoglot English dictionaries including "libre"; about 30 include "gratis"
- Free software philosophy at GNU.org
- For example, the free software definition clarifies the distinction in this way.
- A quote from the Gnu free software definition was used in a section on positive and negative liberty by Guinevere Nell in Rediscovering Fire: Basic Economic Lessons From the Soviet Experiment, Algora, 2010.
- Harnad, Stevan (2003) For Whom the Gate Tolls Journal of Postgraduate Medicine 49: 337-342
- Suber, Peter (2008) Gratis and libre open access SPARC Open Access Newsletter, August 2, 2008
- Harnad, Stevan (2003) On the Deep Disanalogy Between Text and Software and Between Text and Data Insofar as Free/Open Access is Concerned. American Scientist Open Access Forum. August 16, 2003
- Harnad, Stevan (2010) On Open Access: "Gratis" and "Libre". Open Access Archivangelism 691, January 21, 2010
||This article includes a list of references, but its sources remain unclear because it has insufficient inline citations. (September 2010)|
|Look up libre in Wiktionary, the free dictionary.|
|Look up gratis or free of charge in Wiktionary, the free dictionary.|
- Gratis and libre open access. An article by Peter Suber (August 2008) borrowing the gratis/libre distinction from the domain of software and applying it to the domain of peer-reviewed research articles.