Generalization

Inheritance is also called an is-a relationship because the class inherited from another class can be used as the superclass.

When a class represents the shared characteristics of more than one class, it is called a generalization; for example, Vehicle is a generalization of Bike, Car, and Truck. Similarly, when a class represents a special instance of a general class, it is called a specialization, so a Car is a specialization of Vehicle, as shown in the following diagram:

In UML terminology, the relation to describe inheritance is called Generalization.