Hyper-Text Markup Language (HTML) alongside Hyper-Text Transfer Protocol (HTTP) formed the core of Sir Tim Berners-Lee’s world-wide web. As the name implies, HTTP is a markup language, one that combines the text of what is being said with instructions on how to display it.
The other aspect of HTML is its hyper-text nature. Hyper-text refers to text that links to additional resources - primarily the links in the document, but also embedded multimedia.
This ability to author structured pages that linked to other structured pages with a single mouse click is at the heart of the World-Wide-Web.