What term describes the load divided by the original cross-sectional area?

The term that describes the load divided by the original cross-sectional area is stress. In material mechanics, stress is defined as the internal resistance offered by a material to deformation under an applied load, calculated as force per unit area. This fundamental principle helps in understanding how materials behave when subjected to different forces. Stress is typically measured in units such as Pascals (Pa) or pounds per square inch (psi).

Strain refers to the amount of deformation experienced by a material in response to stress, expressed as the change in length divided by the original length, which is a different concept entirely. The term "load" denotes the external force acting upon a structure or material but does not represent the ratio of force to area. Deflection is the amount of displacement of a structural element under load, which again is separate from the concept of stress. Understanding stress is crucial in engineering as it is significant for designing materials and structures that can withstand the forces they encounter without failing.