1 Physics the maximum extent of a vibration or oscillation, measured from the position of equilibrium. the maximum difference of an alternating electrical current or potential from the average value. 2 Astronomy the angular distance of a celestial object from the true east or west point of the horizon at rising or setting. 3breadth, range, or magnitude:the amplitude of the crime of manslaughter lies beneath murder
4 Mathematics the angle between the real axis of an Argand diagram and a vector representing a complex number.