The <concept> element is the top-level
element for a topic that answers the question what is?
Concepts provide
background information that users must know before they can successfully work
with a product or interface. Often, a concept is an extended definition of
a major abstraction such as a process or function. It might also have an example
or a graphic, but generally the structure of a concept is fairly simple.
The <conbody> element is the main body-level
element for a concept. Like the body element of a general topic, <conbody>
allows paragraphs, lists, and other elements as well as sections and examples.
But <conbody> has a constraint that a section
or an example can be followed only by other sections or examples.