Introduction to OOP

Chapter 16: Overriding :

Overriding, Shadowing and Redefinition

Overriding	The type signatures are the same in both parent and child classes, and the method is declared as virtual in the parent class.
Shadowing	The type signatures are the same in both parent and child classes, but the method was not declared as virtual in the parent class.
Redefinition	The type signature in the child class differs from that given in the parent class.