Definition of PageRank 

PageRank is Google’s system of defining the popularity of a web page through evaluating the inbound links (other pages that link to it)

According to Google: These scores are then used along with many other things to determine if a page will rank well in a search (citation from Apr 26, 2007!)

PageRank was the foundation of Google’s algorithm from the first public version of the search engine back in 1998 until Hummingbird in 2015. PageRank was the principal differentiator of Google in the early noughties that gave it a significant competitive advantage and allowed it to rapidly gain domination of the search landscape at that time.

Today, Google no longer communicates on PageRank. It has been very tightly integrated into the very core of Google’s calculations for ranking alongside thousands of other signals… It no longer dominates as it once did.