Google PageRank is [only] one of the methods Google uses to determine a page’s relevance or importance.
Google uses many factors in ranking. Of these, the Google PageRank algorithm might be the best known. Google PageRank evaluates two things: how many links there are to a web page from other pages, and the quality of the linking sites. With Google PageRank, five or six high-quality links from websites would be valued much more highly than twice as many links from less reputable or established sites.