A backlink is simply a link from one website pointing to another. It's one of the most crucial elements of SEO because it tells search engines that your content is trustworthy and worth ranking higher. Think of it like a recommendation — when a reputable site links to yours, Google sees it as a vote of confidence.
Generally speaking, the more quality backlinks a page has, the higher its chances of ranking well. Backlinks come in two main types: Do-follow links pass SEO value and help improve your site's credibility and ranking. No-follow links don't directly boost SEO, but they can still drive traffic to your site. For example, a link in a blog comment section is typically no-follow, while an editorial mention in a news article is usually do-follow.