A quantity that characterizes the order of a phase of a system below its transition temperature. An order parameter has a nonzero value below the transition temperature and a zero value above the transition temperature. An example of an order parameter is magnetization (see magnetism) in a ferromagnetic system. If the phase transition is continuous (i.e. there is no latent heat), the order parameter goes to zero continuously as the transition temperature is approached from below. Disorder parameters are quantities that are nonzero above the transition temperature and zero beneath it. Order parameters are associated with the broken symmetry of a system.