A backlink (also known as an inbound link or incoming link) is created when one website links to another. In the eyes of search engines like Google, a backlink is viewed as a 'vote of confidence'. The more high-quality, relevant websites that link to your page, the more authoritative your page appears, which typically results in higher search rankings.
However, not all backlinks are created equal. A link from a highly trusted, industry-relevant website (like a major news outlet or an established local chamber of commerce) carries significantly more weight than dozens of links from low-quality or spammy directories. Building a strong backlink profile is a core strategy in off-page SEO.