Examples of sections would be chapters,the varIoUs tabbed pages in a tabbed dialog Box,or the numbered sections of a thesis. A Web site’s home page could be split into sections for an introduction,news items,and contact information

The section element represents a generic document or application section…The section element is not a generic container element. When an element is needed for styling purposes or as a convenience for scripting,authors are encouraged to use the div element instead.

Source。

Further Reading。

另见When to use the section element。