ELI5: Explain Like I'm 5

HTML

HTML stands for Hyper Text Markup Language. It is used to create web pages by giving instructions to the web browsers. HTML is like a set of rules with words and letters and symbols. For example, if you wanted to make a heading that said "Hello World!" You would write <h1>Hello World!</h1>. When instructions like this are written and sent to a web browser, it will know how to display it on your screen.