"Hysteresis (hysteresis is like a "memory" of the material, if you press down rubber disks, they tend to back to it's normal uncompressed state as the load of fingers is relieved of structural material, for example the compression of rubber disks, stretching of rubber bands and cords, bending of steel springs, or twisting of torsion bars. Hysteresis is the tendency for otherwise elastic materials to rebound with less force than was required to deform them. "