Introduction Of HTML,What HTML stands for?

HTML stand for Hyper Text Markup Language :

Hyper is the opposite of linear. It used to be that computer programs had to move in a linear fashion. This before this, this before this, and so on.
HTML does not hold to that pattern and allows the person viewing the World Wide Web page to go anywhere, any time they want.
Text is what you will use. English letters, just like you use everyday..
Markup is what you will do. You will write in plain English and then mark up what you wrote.
Language. Some may argue that technically html is a code, but you write html in plain, everyday English language.

HTML stands for HyperText Markup Language. Developed by scientist Tim Berners-Lee in 1990, HTML is the "hidden" code that helps us communicate with others on the World Wide Web (WWW).

When writing HTML, you add "tags" to the text in order to create the structure. These tags tell the browser how to display the text or graphics in the document.

As It is explained in the Venn diagram XHTML is a subset of HTML and XML.
XHTML combines the flexibility of HTML with the extensibility of XML.