Elasticity and Elastic Force: Something that is elastic can return to its original shape after being stretched or compressed. This property is called elasticity. As you stretch or compress an elastic material, it resists the change in shape. It exerts a counter force in the opposite direction. This force is called elastic force. Elastic force causes the material to spring back to its original shape as soon as the stretching or compressing force is released.    
 
Rubber is a good example of how this works- when you stop stretching a rubber band, it goes back to its original shape.