Sectioning is a new semantic markup to define sections on the page. It is mainly used as future expansion of HTML5 webpage and designed to target search engine understanding of your page content. This content type was based on extensive collection of div attributes and modeled after most common div attributes. 

List of sectioning content types:

Header – contains header context

Footer – contains footer context

Section – specifies certain section of the page

Article – article content on the page

Aside – related content to main content on the page

Nav – content that construct navigation on the page

All of these sectioning elements can be styled with the help of CSS.