Backlink

A backlink is a link from another website to yours, and search engines treat each one a little like a recommendation. When a respected site links to a page of yours, it passes on some of its credibility, which can help that page rank higher.

It is like word-of-mouth: a mention from a trusted friend carries far more weight than praising yourself. Backlinks matter because quality links from genuinely relevant, reputable sites are one of the stronger signals search engines use, though a few good links count for much more than many poor or bought ones.