HTML

HTML is the language for describing the structure of Web pages. HTML gives authors the means to:

* Publish online documents with headings, text, tables, lists, photos, etc.

* Retrieve online information via hypertext links, at the click of a button.

* Design forms for conducting transactions with remote services, for use in searching for information, making reservations, ordering products, etc.

* Include spread-sheets, video clips, sound clips, and other applications directly in their documents.

With HTML, authors describe the structure of pages using markup. The elements of the language label pieces of content such as “paragraph,” “list,” “table,” and so on.

(Source: w3c: http://www.w3.org/standards/webdesign/htmlcss)

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HTML5 is a core technology markup language of the Internet used for structuring and presenting content for the World Wide Web. As of October 2014 this is the final and complete fifth revision of the HTML standard of the World Wide Web Consortium (W3C). Its core aims have been to improve the language with support for the latest multimedia while keeping it easily readable by humans and consistently understood by computers and devices. 

(Source: http://en.wikipedia.org/wiki/HTML5)