PageRank is a link analysis algorithm, named after Larry Page and used by the Google web search engine, that assigns a numerical weighting to each element of a hyperlinked set of documents, such as the World Wide Web, with the purpose of "measuring" its relative importance within the set.
The algorithm may be applied to any collection of entities with reciprocal quotations and references [related to webpages]. The numerical weight that it assigns to any given element E is referred to as the PageRank of E and denoted by 
The name "PageRank" is a trademark of Google, and the PageRank process has been patented (U.S. Patent 6,285,999). However, the patent is assigned to Stanford University and not to Google.
Google has exclusive license rights on the patent from Stanford University. The university received 1.8 million shares of Google in exchange for use of the patent; the shares were sold in 2005 for $336 million.
The value of incoming links is colloquially referred to as "Google juice".
