HTML5 is a computer language that lets web pages have pictures, videos, and other features. It stands for HyperText Markup Language and is the newest version of HTML. When you look at a website, you can think of HTML as the instructions for how to show the content. For example, HTML might say "show the picture here", or "make this word big and bold". HTML5 gives instructions for new types of content that weren't around when older versions of HTML were being written. It also makes it easier to write instructions in HTML, so web pages are more efficient.