A model contains a (hierarchical) set of elements that describes the physical system being modeled. It can also contain a set of elements that represent the environment of the system (typically Actors together with their interrelationships), such as Associations and Dependencies.
A model is presented as a package with a small triangle in the upper right corner of the large rectangle. The triangle can be shown in the tab.
The model is defined as a package; that is, it has package properties in the Model Specification window, as shown below.