HTML is basically a computer language that allow website creations.
These websites can be viewed by almost everyone connected to the Internet. It is easy to learn and quite powerful in what it allows you to create.
HyperText is a special method that some people to surf around on the web. Also by clicking on special text called hyperlinks, they bring you to the next page. Markup is what HTML tags do to the text inside them. They mark it as a certain type of text.