The letters HTML stand for HyperText Markup Language. HTML is the standard markup language used for creating and structuring content on the web. It allows developers to define elements such as headings, paragraphs, links, images, and multimedia. Using HTML, web pages are organized in a way that can be rendered by web browsers, facilitating a rich user experience. HTML forms the backbone of web development, often combined with CSS (Cascading Style Sheets) for styling and JavaScript for interactivity, enabling the creation of dynamic and visually appealing websites.