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.