Constants are defined within the scope of the current class and are made available to all child classes, unless they're overridden.
Pi = 3.141592 class OtherPlanet Pi = 4.5 # from w w w . ja v a 2s . com def OtherPlanet.circumference_of_circle(radius) radius * 2 * Pi end end puts OtherPlanet.circumference_of_circle(10) puts OtherPlanet::Pi puts Pi
Here, the code demonstrates that constants have scope within the context of classes.
The OtherPlanet class has its own definition of Pi.