Override a method -> replace a superclass method with a child class by naming it the same (e.g. toString() )
Polymorphism: objects and methods can have more than one form
objects: If shark extends fish, a shark can be treated 3 different ways because
a shark is-a fish,
a shark is-a shark,
a shark is-a object
functions: By overloading the methods they can have several forms. e.g.
foo(int x, int y)