Rigid Body - A body which retains the same form under applied stresses. That is, there is no twisting or bending in the objects shape.

In reality, there are no rigid bodies. Practically, however, some bodies are considered rigid under actual loads that are limited.. Because of kinematic mounting which reduces stresses, a supertable may act practically as a rigid body.

An object which expands uniformly due to a temperature change may still be considered rigid unless temperature gradients (or other changing stresses) alter the form.