Shear Modulus
The shear modulus is one of several quantities for measuring the strength of materials. All of them arise in the generalized Hooke's law. Young's modulus describes the material's response to linear strain (like pulling on the ends of a wire), the bulk modulus describes the material's response to uniform pressure, and the shear modulus describes the material's response to shearing strains. Anisotropic materials such as wood and paper exhibit differing material response to stress or strain when tested in different directions. In solids, there are two kinds of sound waves, pressure waves and shear waves. The speed of sound for shear waves is controlled by the shear modulus.
See Also
Young's Modulus and Bulk Modulus.