HTML is a Programming Language. It’s full form is Hyper Text Markup Language.
This language is invented by Swish Physician Tim Berners-Lee in 1990 AD at European Laboratory, Switzerland.
Definition:
HTML is a simple scripting language used to create hypertext documents. Hyper text document is a piece of text that works as link.
Before HTML, it was SGML which is abbreviation of Standard Generated Markup Language.