Search Engine Optimization (SEO) is the process of optimizing a website or web page to increase its visibility in search engines, such as Google and Bing. SEO involves using techniques such as keyword research, content optimization, link building, and more to help websites rank higher in search engine results pages. By optimizing your website for SEO, you can improve its visibility and drive more organic traffic to your site, which can ultimately lead to an increase in sales and revenue.