stress

1. Engineering: Load (force) per unit area that tends to deform the body on which it acts. Compressive stress tends to squeeze a body, tensile stress to stretch (extend) it, and shear stress to cut it. See also strain.

2. Psychology: (1) As a cause: mental, physical, or social, force or pressure that puts real or perceived demands on the body, emotions, mind, or spirit, and which (when it exceeds the stress-handling capacity of the individual) lead to a breakdown. (2) As an effect: physiological effect produced in an organism in its attempts to cope (called adaptive response) with the demands created by a stressor.