Plasticity, in physics, describes the mechanical ability of a material to undergo permanent deformation under applied stress without fracturing. This property is fundamental to material science and determines how much a solid can be shaped or drawn before reaching its breaking point. Materials with high plasticity are capable of sustaining significant plastic strain, which represents the deformation that remains even after the stress is removed. Mechanically, this process often involves the irreversible sliding or shifting of crystalline planes within the material's internal structure. The extent of plastic deformation is crucial for engineering applications, influencing the design of structures that must withstand stresses, bending, or continuous forming processes.