Semantic elements are HTML tags that convey meaning about the content they contain. Unlike generic tags like <div> or <span>, semantic elements provide context to both browsers and developers. Examples include <header>, <footer>, <article>, and <section>, which help structure a webpage in a meaningful way. Using semantic elements improves accessibility and search engine optimization (SEO). Screen readers can better interpret the content, making it easier for users with disabilities to navigate. Additionally, search engines can understand the structure and relevance of the content, potentially improving the page's ranking in search results.