It comes from the Greek language and it means many forms. It is a feature that allows one interface to be used for a general class of actions. The specific action is determined by the exact nature of the situation. Consider a stack(which is last-in first out). You might have a program that requires three types of stacks. One with integers, one with floating-points, and another one with characters. The algorithm that implements each stack is the same, even though the data being stored is different.