SEO stands for search engine optimization and involves optimizing websites to increase their relevance for specific search terms to attract organic search traffic. This is done through techniques like on-page editing, link building, and targeting different types of searches like image, local, and mobile searches. The goal is to understand how search engines work and what users search for in order to help websites rank higher in search results. While SEO can be complex, the basics are easy to understand and free education is widely available online to help websites improve their search visibility.