Hysteresis is a phenomenon where the state of a system depends not only on its current conditions but also on its past history. This is commonly observed in materials like ferromagnetic substances, where the magnetization of the material does not immediately return to its original state after an external magnetic field is removed. Instead, it follows a different path, creating a loop on a graph that represents the relationship between magnetization and the applied magnetic field. In addition to magnetism, hysteresis can also occur in other fields, such as mechanical systems and thermodynamics. For example, in a rubber band, stretching it and then releasing it may not return it to its exact original shape, demonstrating how past deformation affects its current state. Understanding hysteresis is important in various applications, including engineering and material science.