Block Elements [June 24, 2011, 1:13 a.m.]
There are several primary block elements used in HTML5. We will look at some new and old tags that complement the <head> and <body> duo.
The <header> tag is a container for introductory materials in a document or section. <header> can be used multiple times in a document and usually contains at least one <h1>-<h6> element (in order to validate).
<header> <h1>Section/Document Header</h1> <p>A brief description of this section/document</p> </header>
The <nav> tag is used to demarcate a section containing navigation anchors (links) to other content or sections. The anchors can be nested within a list such as an unordered list <ul>.
<nav> <h1>Navigation</h1> <ul> <li><a href="#home">Home</a></li> <li><a href="#contact">Contact Us</a></li> </ul> </nav>
The <article> tag designates a region of a document that is self-contained. <article> can be an article, blog post, news story, etc.
<article> <img src="image.webp" alt="An image." /> This is the content for the article. </article>
The <aside> tag contains information that is tangentially related to to the primary content. Examples can include anecdotes, sidebars, external links, keyword definitions, etc.
HTML5 Doctor: Aside revisited
w3c: The aside element
w3schools: HTML5 aside tag