A form of SGML intended for use on the World Wide Web. A particular feature of HTML is the use of tags that include information about hyperlinks, either to other places in the document or to other documents on the Web. Text surrounded by these tags is usually underlined and in a different colour when displayed by the browser, and can be clicked to jump to the link. HTML has a set of basic tags, mostly defining format rather than content, although some browsers use nonstandard tags. The current version is HTML5. See also CSS, DHTML, XHTML, XML.

http://www.w3.org/TR/html5/ The HTML (version 5) specification