In inheritance, the inheriting class is called the subclass and the class being inherited from is call the superclass. A subclass inherits all of its superclass' variables and methods. Instances can be implemented any non-abstract class. Subclasses are specialization of their superclasses. A subclass may add variables, but it cannot delete those inherited from the superclass.
Object instances are instances of a class.
The most common relationships in Smalltalk are the inter-class relationships defined by the inheritance class hierarchy. In addition, an object is related to another object when it has a pointer to that object. This serves the need to link objects together and coordinate the behavior between them. A Smalltalk object's instantiated variables are stored in its private memory and called instance data. Smalltalk does not support public attributes.