Modulus of elasticity
Definition
A modulus of elasticity, or elastic modulus, for a substance or object is defined as the ratio of the applied stress on the object (intended to deform it) and the strain, which is the fractional extent of deformation of the object.
It can also be defined as the slope of the stress-strain curve in the elastic deformation region, which is the region where it satisfies a rough approximation of Hooke's law.