What Is Google PageRank?
Google PageRank (PR) is a score from 0 to 10 that reflects the authority of a page based on the number and authority of links to that page. The score is logarithmic such that PR7 has roughly 8 times more authority than PR6 (which has 8 times more authority than PR5).
The data which Google releases publicly is often several months old and inaccurate. It is not the same data they use to rank websites. It is still useful as a very broad estimate of a page's authority.
Note, there is no "Domain PageRank", but often the PageRank of a domain's homepage is used as an estimate of an entire domain's authority.What Is Google PageRank?