What is polymorphism, what is it for, and how is it used?

Question

What is polymorphism, what is it for, and how is it used?

Answer 1

(I was browsing another article on something entirely different.. and polymorphism popped up... Now I thought that I knew what Polymorphism was.... but apparently not in this beautiful way explained.. Wanted to write it down somewhere.. better still will share it... )

http://www.eioba.com/a/1htn/how-i-explained-rest-to-my-wife

read on from this part:

..... polymorphism. That's a geeky way of saying that different nouns can have the same verb applied to them.