Backlinks are hyperlinks linking one webpage or website to another webpage or website. Backlinks are an important piece of SEO (search engine optimization) and search engine rankings because they show that the page being linked to is a good resource for a given topic.
The more backlinks a given webpage has, the more credibility it has in the eyes of the search engines. Ultimately, a webpage with many pages linking back to it is likely to have a higher ranking on search engine results pages (SERPs).