Open access

Barrier-free online access, in this case to scholarly online literature. Open access eliminates two kinds of access barriers: (1) price barriers and (2) permission barriers such as copyright and licensing terms. Open-access archives and open-access journals offer barrier-free access to their online content.
[Source: Guide to the open access movement [link: http://www.earlham.edu/~peters/fos/guide.htm], Peter Suber]