Backlink

From the point of view of a given web resource (referent), a backlink is a hyperlink on another web resource (the referrer) that points to the referent. A web resource may be (for example) a website, web page, or web directory. Some other words for backlink are incoming link, inbound link, inlink, inward link, and citation. The "back" in "backlink" is to distinguish it from the types of hyperlink that are contained within the given web resource, which are either internal links or outbound links. The web resource links out with outbound links and other web resources link back to it with backlinks.

A backlink is a reference comparable to a . The quantity, quality, and relevance of backlinks for a web page are among the factors that search engines like Google evaluate in order to estimate how important the page is. PageRank calculates the score for each web page based on how all the web pages are connected among themselves, and is one of the variables that Google Search uses to determine how high a web page should go in search results. This weighting of backlinks is analogous to of books, scholarly papers, and academic journals. A Topical PageRank has been researched and implemented as well, which gives more weight to backlinks coming from the page of a same topic as a target page.