Deformation (noun)

1. A change of shape or form, especially when unintended or undesired.
2. The act of changing the natural, normal, or original shape or form of something.

Origin:

Late middle english (in the sense "corruption, perversion"): from latin deformatio(n-), from deformare "distort" (see deform).

Examples:

1. The metal had suffered extensive deformation in the accident.
2. The deformation of the plastic was studied under different loads.
3. The deformation of the structure was caused by the heavy weight.
4. The deformation of the metal was measured after it was subjected to heat.
5. The deformation of the material was found to increase with temperature.