SEO stands for Search Engine Optimization. It is a digital marketing strategy aimed at improving a website's visibility and ranking in search engine results pages (SERPs). The primary goal of SEO is to attract organic (non-paid) traffic to a website by optimizing its content, structure, and various other factors to make it more search engine-friendly.

Search engines like Google, Bing, and Yahoo use complex algorithms to determine which web pages should appear in response to a user's search query. SEO involves various techniques and best practices to ensure that a website's content matches what users are searching for and to increase the website's chances of ranking higher in search results.