Open access (OA) is a set of principles and a range of practices through which research outputs are distributed online, free of cost or other access barriers. Through licensing via an open license (usually a Creative Commons License), freely available outputs can also be legally shared, reused and adapted. Hence, open access is more than just free access. (Text adapted from Open Access Australasia [CC BY]).
The glossary in this guide provides definitions of the major concepts in the OA space.