A node class is a class that is defined as : > Relies on the base class for services and implementation, > It Provides a wider interface to the users than its base class, > It Relies primarily on virtual functions in its public interface. >It Depends on all its direct and indirect base class. > It can be understood only in the context of the base class. > It can be used as base for further derivation. > It can be used to create objects. > A node class is a class that has added new services or functionality beyond the services inherited from its base class.