What physical property allows a material to return to its original shape after deformation?

Resilience is the physical property that allows a material to return to its original shape after being deformed. It measures a material's ability to absorb energy when it is deformed elastically and then release that energy upon unloading. This characteristic is crucial in applications where materials experience temporary stresses and need to recover their original geometry without permanent deformation.

In contrast, yield strength indicates the maximum stress a material can withstand before it begins to deform plastically, which means it will not return to its original shape. Toughness reflects a material's ability to absorb energy and deform without fracturing, representing a combination of strength and ductility, but it does not specifically address the recovery aspect. Ductility refers to a material's ability to stretch and deform under tensile stress, typically leading to permanent shape changes. Resilience, therefore, is the best answer as it directly relates to a material's capacity to revert to its original form after deformation.