Stress may refer to: Mechanical Stress (mechanics), the average amount of force exerted per unit area. It is the internal resistance a material offers to being deformed and is measured in terms of the applied load. Yield stress, the stress at which a material begins to deform plastically Compressive stress, the stress applied to materials resulting in their compaction. It is the ability of a material to resist being crushed. Biological Stress (biological), physiological or psychological str… (More on Stress)