Class A is a Java class that extends another class (Class B) and contains its own methods and/or fields in addition to those inherited from Class B.
Class A cheat sheet for homework
The ability for one class to extend another class, inheriting its methods and fields.
When a subclass provides its own implementation of a method defined in its superclass.
The ability of an object to take on many forms, allowing different classes to be used interchangeably.