Semantic markup refers to the practice of using HTML elements to convey the meaning, structure, and context of content within a web page, rather than solely focusing on the presentation or appearance. Semantic HTML elements describe their meaning to both the browser and the developer, making the content more understandable, accessible, and meaningful for humans and search engines.

Here are some key aspects of semantic markup:

1. **Clear Structure:**
– Semantic HTML elements provide a clear structure to web documents, making it easier to understand the relationship between different parts of the content.
– For example, using `<header>`, `<nav>`, `<main>`, `<section>`, and `<footer>` elements to organize the content of a web page.

2. **Meaningful Content:**
– Semantic elements describe the purpose or meaning of the content they enclose.
– For instance, using `<article>` to represent a self-contained piece of content, such as a blog post or news article.

3. **Accessibility:**
– Semantic markup improves accessibility by providing meaningful labels and landmarks for assistive technologies like screen readers.
– Elements like `<nav>`, `<header>`, `<footer>`, `<main>`, and `<aside>` help screen readers and other assistive technologies to understand the structure and navigate the content more effectively.

4. **Search Engine Optimization (SEO):**
– Search engines rely on semantic HTML to understand the content and context of web pages.
– Using semantic elements appropriately can improve the search engine ranking of a website by providing clear indications of the content’s relevance and importance.

5. **Future Compatibility:**
– Semantic HTML ensures future compatibility and adaptability to evolving web standards and technologies.
– It makes it easier to update and maintain websites, as the structure and meaning of the content remain clear regardless of changes in presentation or styling.

Examples of semantic HTML elements include `<header>`, `<nav>`, `<main>`, `<section>`, `<article>`, `<aside>`, `<footer>`, `<figure>`, `<figcaption>`, `<address>`, and more. By utilizing semantic markup effectively, web developers can create well-structured, accessible, and SEO-friendly websites that provide a better user experience for all users.