An HTML tag, short for Hypertext Markup Language tag, is a code used to structure and format content on a webpage. These tags act as instructions for web browsers to display text, images, videos, and other elements in a specific way. They are enclosed in angle brackets (< >) and consist of an opening tag and a closing tag, with the content in between. HTML tags are essential for creating visually appealing and organized web pages, and they play a crucial role in the overall design and functionality of a website. Without HTML tags, the internet as we know it would not exist, making them a fundamental component of web development.