Dynamic HTML means that you can use HTML to create web pages that will change in response to things that the person using it does. For example, when you type something into an online search box and press enter, the web page can change to show you the results of your search. It can also work in other ways - when you click on a button on a web page it can make something happen on the page. HTML is the language that computers use to display web pages on the internet, and Dynamic HTML makes it possible for web pages to look different or do something different based on the actions of the person using it.