A link from another website pointing to your site. Think of backlinks as votes of confidence from other websites saying your content is worth sharing. Search engines see backlinks as a major ranking factor because they indicate your content is valuable and trustworthy. The more quality backlinks you have, the better your chances of ranking higher in search results. Not all backlinks are equal though. A link from a popular, relevant website in your industry carries much more weight than a link from a random blog.