HTML5 is a markup language used for structuring and presenting content on the World Wide Web. It is the fifth and current version of the HTML standard. It was published in October 2014 by the World Wide Web Consortium (W3C) to improve the language with support for the latest multimedia, while keeping it both easily readable by humans and consistently understood by computers and devices such as web browsers, parsers, etc.
HTML5 is the latest evolution of the standard that defines HTML. The term represents two different concepts: It is a new version of the language HTML, with new elements, attributes, and behaviors, and a larger set of technologies that allows more diverse and powerful Web sites and applications.