Definitions for "Content model"
In a DTD, the definition of the content (Element or character) that can be nested within any given element.
A description of the structure of child elements and text nodes (independent of attributes). The content model is simple when there is a text node but no elements, complex when there are element nodes but no text, mixed when there are text and element nodes, and empty when there are neither text nor element nodes.
a pattern that you set up to declare what child element types are allowed inside an element and the order of those child elements
a collection of related Content Types and Aspects