Hooke's Law is a basic principle in physics that describes the relationship between the amount of deformation (stretch or compression) of an elastic material and the force applied to it. It states that the deformation of a material is directly proportional to the force applied to it, as long as the material remains within its elastic limit. Hooke's law commonly used in engineering and physics to calculate the deformation of materials and to design structures and devices that can withstand external forces.