Young's modulus is a measure of the stiffness of a material. It quantifies how much a material will stretch or compress when a force is applied. Specifically, it is defined as the ratio of tensile stress (force per unit area) to tensile strain (proportional deformation in length). A higher value indicates a stiffer material that deforms less under stress. This property is crucial in engineering and materials science, as it helps in selecting appropriate materials for structures and components. For example, metals typically have high Young's modulus values, making them suitable for construction, while rubber has a low value, allowing it to stretch easily.