Libre means free as in freedom.
This posting was prompted by the thread “[okfn-discuss] Problems of nomenclature“.
The meaning of “libre” is well established and is correctly used (at least today) (by definition) on the following pages:
These definitions are rooted in the free software definition.
The licensing of a resource either complies with the definition and the resource is a “libre resource”, or it doesn’t and the resource is non-libre. There is no “semi-libre”. The Free Software Foundation dropped the term “semi-free” some time ago and it has not been picked up and (mis)used systematically (if at all) by libre knowledge communities.
The Creative Commons Attribution-ShareAlike licence is the most “pro-freedom” licence in the Creative Commons suite. It is unambiguously a libre licence. The ShareAlike in this case is an assurance of freedom for users of the work and of future derived works – in the face of the current (highly restrictive) state of copyright which came about along these lines: see Brief History of Copyright.
The Creative Commons Attribution-Non-commercial-ShareAlike licence, on the other hand, although it assures shareability, perpetuates a restriction on use, even of future derived works (i.e. non-commercial use only). It is unambiguously not a “libre licence”.
A few Libre Licences are listed here.
The Say Libre essay encourages the various “open” communities to say “libre” rather than “open” in those cases where “libre” is actually meant – i.e. when the licence upholds all of the freedoms (e.g. when the resource to which they are referring is licensed cc-by, cc-by-sa, or is in the public domain/ CC0.
The “open education” community, for example, includes some institutions which use the NonCommercial restriction in their licensing.
It helps with clarity of thinking to avoid the term “IP” – see Words to Avoid (or Use with Care) Because They Are Loaded or Confusing. We are not talking about anything that has the rivalrous properties of “property”.
In the context of software, some people say “free/libre and open source” software (FLOSS) which covers both open source software and libre software – with the understanding that all libre software is open source (in the sense that the source code is available) but some open source software is non-libre (the source code is available but restricted in use and/or is dependent on some other non-libre software).
For more on Libre Knowledge see the Libre Knowledge pages on WikiEducator.