Hypertext Markup Language, commonly known as HTML, is the standard language used to create and design documents on the World Wide Web. It provides the structure for web pages by using a series of elements and tags that define the content and layout, allowing browsers to render text, images, and other multimedia. HTML is essential for web development, as it enables developers to build interactive and visually appealing websites. By combining HTML with other technologies like CSS for styling and JavaScript for functionality, developers can create dynamic web applications that enhance user experience.