Magnetic hysteresis refers to the phenomenon where the magnetization of a material lags behind the applied magnetic field. When a magnetic field is applied to a material, it becomes magnetized, but when the field is removed, the material does not return to its original state immediately. Instead, it retains some magnetization, which is a key characteristic of ferromagnetic materials. The hysteresis loop is a graphical representation of this behavior, showing the relationship between the applied magnetic field and the resulting magnetization. The area within the loop indicates energy loss due to the material's internal friction during magnetization and demagnetization cycles, which is important in applications like transformers and magnetic storage devices.