Force per unit area, often thought as force acting through a small area within a plane. It can be divided into components, normal and parallel to the plane, called “normal stress” and “shear stress”, respectively. “True stress” denotes the stress where force and area measured at the same time. “Conventional stress”, as applied to tension and compression tests, is force divided by the original area. “Nominal stress” is the stress computed by simple elasticity formulas, ignoring stress raisers and disregarding plastic flow; in a notch bond test, for example, it is bending moment divided by minimum section modulus.