HTML (HyperText Markup Language) is the standard language used for creating and structuring content on the web. It provides the foundation for web pages by defining elements such as headings, paragraphs, links, images, tables, and more. HTML uses a system of tags and attributes to describe the structure and presentation of web content. It is essential for web development and works in conjunction with CSS (Cascading Style Sheets) and JavaScript to create interactive and visually appealing websites.