physical damage

Damage to objects caused by mechanical rather than chemical means and resulting in cracks, chips, splits, tears, dents, punctures, breaks, scratches, scuffs and abrasions, as well as soiling, wear and tear, warping, shrinkage, separation of layers of composite materials, graffiti and insect attack. 

The top of book spines often become weak and torn, as they are repeatedly pulled from the shelves by this edge. Photo courtesy of the State Library of Victoria.