SEO, or Search Engine Optimization, is the practice of improving a website's visibility on search engines like Google. By optimizing content, structure, and technical aspects of a site, businesses aim to rank higher in search results, making it easier for users to find them. Effective SEO involves using relevant keywords, creating quality content, and ensuring a user-friendly experience. It also includes building backlinks from other reputable sites. Overall, SEO helps drive organic traffic, which can lead to increased engagement and conversions for businesses online.