Search engine optimization (SEO) is the process of increasing the quality and quantity of website traffic by increasing the visibility of a website or a web page to users of a web search engine.
SEO refers to the improvement of unpaid results (known as "natural" or "organic" results) and excludes direct traffic/visitors and the purchase of paid placement.
SEO may target different kinds of searches, including image search, video search, academic search, news search, and industry-specific vertical search engines.