Search engine optimization (SEO) is a set of methodologies aimed at improving the visibility of a website in search engine listings. The term also refers to an industry of consultants that carry out optimization projects on behalf of client sites.

Also known as website optimisation. This is a process of altering the design, content and link network of a site in accordance with the latest search engine scoring formulas. The aim at all times is to improve a site's position on search results pages.