hysteresis(n = noun.phenomenon) - the lagging of an effect behind its cause; especially the phenomenon in which the magnetic induction of a ferromagnetic material lags behind the changing magnetic field;
is a kind of physical phenomenon

   A lagging or retardation of the effect, when the forces acting upon a body are changed, as if from velocity or internal friction; a temporary resistance to change from a condition previously induced, observed in magnetism, thermoelectricity, etc., on reversal of polarity. [1913 Webster]

hysteresis, n. Physics the lagging behind of an effect when its cause varies in amount etc., esp. of magnetic induction behind the magnetizing force.

Etymology:
Gk husteresis f. hustereo be behind f. husteros coming after