Semantic HTML refers to the use of HTML elements that convey meaning beyond just presentation. It involves using HTML tags and attributes in a way that reflects the content and structure of the web page, making it more accessible to both humans and search engines. The element clearly describes its meaning to both the user and the search engine.

For example, instead of using a generic <div> element to define a section of a web page, semantic HTML would use more specific tags such as <header>, <nav>, <main>, <article>, <section>, <aside>, <footer>, etc., depending on the purpose and hierarchy of the content. For SEO purposes, the <h1> tag is considered one of the most important semantic elements to use in your website.

By using semantic HTML, web developers can improve the accessibility and usability of their websites, as it provides more meaningful context to assistive technologies like screen readers. It can also improve search engine optimization (SEO), as search engines can better understand the content and structure of the web page, making it more likely to rank higher in search results.