From the W3C process documentation on http://www.w3.org/2005/10/Process-20051014/tr.html#q74
A Recommendation progresses through five maturity levels:
1.Working Draft (WD)
2.Last Call Working Draft
3.Candidate Recommendation (CR)
4.Proposed Recommendation (PR)
5.W3C Recommendation (REC)
Candidate Recommendation (CR)
A Candidate Recommendation is a document that W3C believes has been widely reviewed and satisfies the Working Group's technical requirements. W3C publishes a Candidate Recommendation to gather implementation experience.
Proposed Recommendation (PR)
A Proposed Recommendation is a mature technical report that, after wide review for technical soundness and implementability, W3C has sent to the W3C Advisory Committee for final endorsement