inequality (n.)

early 15c., "difference of rank or dignity," from Old French inequalité (14c., Modern French inégalité) and directly from Medieval Latin inaequalitas, from Latin inaequalis "unequal, unlike, different (in size); changeable, inconstant," from in- "not, opposite of" (see in- (1)) + aequalis "equal" (see equal). In reference to magnitude, number, intensity, etc., from 1530s.