👉 Stiffness is a measure of how much resistance an object has to change its shape. In the context of materials and structures, stiffness refers to the amount of force required to deform an object in response to external forces. The higher the stiffness value, the more resistant an object is to changes in shape or deformation due to external forces. Stiffness can be measured using various methods such as bending test, cantilever test, etc.