"When the Bethesda and Berlin statements came out (June and October 2003) they followed the Budapest statement in calling for the removal of both price and permission barriers. As a result, all three components of the Budapest-Bethesda-Berlin (BBB) definition of OA now call for both sorts of free online access.
But unfortunately we still don't have widely accepted terms for the two sorts of free online access: (1) the kind which removes price barriers alone and (2) the kind which removes price barriers and at least some permission barriers. This gap in our vocabulary has caused confusion and conflicts, not least because it created pressure to use the term "open access" for each. For now, my choice is to use "gratis" and "libre". They are accurate, neutral, and descriptive. In the neighboring domain of free and open source software, they exactly express the distinction I have in mind".
It means free to read.
Libre is cost free & permission free
It means free to use.
Heather Morrison is a fan of these new terms, and I think they are going to catch on (although some are confused). I do still think that 'real' open access is more than just giving it away for free - permission barriers matter, and others like Jim Till agree. That the initial suggestions for gratis and libre were 'weak OA' and 'strong OA' speaks volumes.