When we apply some force on a body, the body has a tendency to resist the applied force. So stress is the resistive force developed in a body per unit area. Shear stress is resistive force developed per unit area in a body due to the applied Shear force. Shear force causes shape changes without changing the volume of the body.
Strength is the ability of a material to resist external load against failure. Strength is property and fixed for a particular material. And strength is primary design factor.
Shear strength is the ability of the material to resist shear load until failure.
The main difference between these two terms is “shear strength is a property and is constant for material. Shear stress is varies according to the load applied.
Shear strength is the maximum shear stress developed at the time of failure
