Noun
shear modulus (plural shear moduli)
A measure of the elastic shear stiffness of a material, defined as the ratio of shear stress to shear strain.
Synonym: modulus of rigidity
Fluids are substances that have zero shear modulus or, in simpler terms, a fluid is a substance which cannot resist any shear force applied to it. Source: Internet
Its estimated shear modulus is similar to that of lead. Source: Internet
The Born criterion is based on rigidity catastrophe caused by the vanishing elastic shear modulus, e.g. when the crystal no longer has sufficient rigidity to mechanically withstand load. Source: Internet