HyperText Markup Language (HTML) is the standard markup language used to create web pages. It defines the structure and content of a webpage by using a system of tags and attributes. HTML tags specify elements like headings, paragraphs, images, links, and lists, allowing browsers to render and display the webpage properly. HTML forms the foundation of web development, along with CSS (Cascading Style Sheets) for styling and JavaScript for interactivity. Modern versions like HTML5 have introduced new features, such as multimedia support and improved accessibility, enhancing the functionality and performance of websites.