Model
The model is a collection of entities. These entities are all connected to each other through associations. Each association can be described by a relationship. The types of relations are zero to one, one, and many. Each entity also has properties. The most common type is a scalar property.
Example:
There are two entities, cars and wheels. The relationship would be one to many, because each wheel has one car, and each car has many wheels.
Below is en example diagram of a model:
