Polymorphism

Polymorphism is the ability of different functions to be invoked with the same name. There are two forms.
Static polymorphism is the common case of overriding a function by providing additional definitions with different numbers or types of parameters. The compiler matches the parameter list to the appropriate function.
Dynamic polymorphism is much different and relies on parent classes to define virtual functions which child classes may redefine. When this virtual member function is called for an object of the parent class, the execution dynamically chooses the appropriate function to call - the parent function if the object really is the parent type, or the child function if the object really is the child type. This explanation is too brief to be useful without an example, but that will have to be written latter.