Rebound
Rebound is how high or fast something bounces back after hitting a hard surface.
Think of it this way
A rubber ball dropped on a tile floor shows rebound well. It hits the floor and squishes flat for a split second. Then it springs back to its round shape and pushes off the floor. A bouncier ball stores more energy and shoots back up higher.
Explaining rebound by grade level
Drop a drumstick on the floor. It bounces back up. That bounce is a rebound. Hard sticks bounce higher than soft ones.