What does the <meta> tag define in HTML documents?

The tag is used in HTML documents to provide structured metadata about the web page, including essential information such as the character set, page description, keywords, author of the document, and viewport settings for responsive design. This information is not visually displayed on the web page but is crucial for search engines, browsers, and other web services to understand the content and behavior of the page.

By defining character set information, for example, it ensures that browsers render the text correctly. Providing descriptions helps search engines summarize the page in search results, influencing search engine optimization (SEO). Therefore, identifying the tag's role in conveying this information clearly demonstrates its importance in web development and document structuring.