Question

Define Elasticity ?

Answer 1

Do you want a mathematical definition, or a physics definition?

Answer 2

Mathematical

Answer 3

@ujjwal

Answer 4

when you say mathematical, do you mean "formula"?

Answer 5

"A measure of a variable's sensitivity to a change in another variable."
From investopedia.com

Answer 6

"Elasticity is a measure of responsiveness. The responsiveness of behavior measured by variable Z to a change in environment variable Y is the change in Z observed in response to a change in Y. Specifically, this approximation is common:

elasticity = (percentage change in Z) / (percentage change in Y)"

from about.com economics glossary.