A tag is a fundamental concept in web development, particularly in HTML (HyperText Markup Language). Tags are used to create elements on a webpage, such as headings, paragraphs, links, and images. Each tag typically consists of an opening and closing part, with content in between, allowing browsers to render the content appropriately. Tags help organize and structure the content of a webpage, making it easier for both users and search engines to understand. For example, the <div> tag is used to define a division or section, while the <a> tag creates hyperlinks to other pages or resources, enhancing navigation and interactivity.