Define "stress" in the context of materials science.

In materials science, "stress" is defined as the internal force per unit area developed in a material when it experiences an external load or force. This means that stress quantifies the intensity of the internal forces that arise within a material as it undergoes deformation, which can be due to tensile, compressive, or shear forces. It is typically measured in units like pascals (Pa) or pounds per square inch (psi). Understanding stress is crucial for engineers and materials scientists, as it helps in predicting how materials will behave under different loading conditions and assists in designing components that can withstand those conditions without failing.

The other options refer to different aspects of materials or their behavior. The weight of the material itself relates to gravitational force rather than internal response to stress. The temperature at which materials break down pertains to thermal properties rather than mechanical stress. The rate of wear on a material involves wear mechanisms and is not a direct measure of stress in a material.