Open Access (OA) concepts have unique terminology. Some terms are widely used in "open" content/software/etc communities, but other terms only apply to OA academic research literature.
Gratis and Libre
- "Gratis": materials are available free of charge, but not necessarily with any more rights of re-use than traditional, paid-access materials
- "Libre": materials are freely available AND free of limitations on use or manipulation.
The free and open source software movement calls gratis "free as in beer" and libre "free as in speech".
Gold and Green
- "Gold OA": materials are openly available in their original place of publication, through various publication-based models of open access.
- "Green OA": materials made openly available somewhere other than the original place of publication, usually via author self-archiving