There are mainly 6 new semantic elements which have been introduced in HTML 5. The semantic element names are header, nav, section, article, aside, and footer. Note that semantic element is such element which tells clearly its meaning to the browser as well as the developer.
1. header Semantic Element of HTML 5
In past, header was defined within div with id="header" where div is a non-semantic element. Now in HTML 5, a new semantic element has been introduced with "header". Its purpose is the same as that div with id="header" but now the element has a proper meaning to the browser and developer.
2. nav Semantic Element of HTML 5
In it, navigational links are defined. Note that normally nav semantic element comes only in header but it can also come to other places like footer to mention footer links.
3. section Semantic Element of HTML 5
In it, a complete section is defined. It contains heading and other text.
4. article Semantic Element of HTML 5
In it, we define an independent article like Blog post, comment etc.
5. aside Semantic Element of HTML 5
In it, we define those thing which are not part of page content and aside from it.
6. footer Semantic Element of HTML 5
In it, we define those things which were defined in a div with id="footer". It contains copyright statement. In addition to it, it can contain navigational links if required.