Kinetic energy changes in collisions

[Jacob Aron]

Is the coefficient of restitution of two particles a measure of the percentage of kinetic energy retained after a collision? My textbooks and Google are no help. If it isn't, what is it a percentage of?

[StephenPrivitera]

I've come to love this site. You will too.
http://scienceworld.wolfram.com/physics/CoefficientofRestitution.html