the state or quality of being ample, especially as to breadth or width; largeness; greatness of extent.

large or full measure; abundance; copiousness.

mental range, scope, or capacity.

Physics. the absolute value of the maximum displacement from a zero value during one period of an oscillation.

Electricity. the maximum deviation of an alternating current from its average value.

Astronomy. the arc of the horizon measured from the east or west point to the point where a vertical circle through a heavenly body would intersect the horizon.

astronomythe angular distance along the horizon measured from true east or west to the point of intersection of the vertical circle passing through a celestial body

Also called: argumentmaths(of a complex number) the angle that the vector representing the complex number makes with the positive real axis. If the point (x, y) has polar coordinates (r, θ), the amplitude of x + i y is θ, that is, arctan y/xCompare modulus (def. 2) See also Argand diagram

physicsthe maximum variation from the zero or mean value of a periodically varying quantity

Word Origin for amplitude

C16: from Latin amplitūdō breadth, from amplus spacious

1540s, from Middle French amplitude or directly from Latin amplitudinem (nominative amplitudo) "wide extent, width," from amplus (see ample). Amplitude modulation in reference to radio wave broadcast (as opposed to frequency modulation) first attested 1921, usually abbreviated a.m.

PhysicsOne half the full extent of a vibration, oscillation, or wave. The amplitude of an ocean wave is the maximum height of the wave crest above the level of calm water, or the maximum depth of the wave trough below the level of calm water. The amplitude of a pendulum swinging through an angle of 90° is 45°. Compare frequency.

ElectronicsThe amount by which a voltage or current changes from zero or an average value.