What Does HTML5 Mean?
Hypertext Markup Language revision 5 (HTML5) is markup language for the structure and presentation of World Wide Web contents. HTML5 supports the traditional HTML and XHTML-style syntax and other new features in its markup, New APIs, XHTML and error handling.
Techopedia Explains HTML5
HTML5 is an effort is to bring order to web development chaos by organizing common practices, embracing implementations from various browsers. It is massive, with over 100 specifications as part of the HTML5 specs. Understanding this, you can simplify by thinking of HTML5 this way. HTML5 is simply just an umbrella term for the next generation of web apps an how functionality will be expanded with better markup (HTML), better style (CSS), and better interactivity (JavaScript).