# amplitude

## amplitude

[am-pli-tood, -tyood]
noun
1.
the state or quality of being ample, especially as to breadth or width; largeness; greatness of extent.
2.
large or full measure; abundance; copiousness.
3.
mental range, scope, or capacity.
4.
Physics. the absolute value of the maximum displacement from a zero value during one period of an oscillation.
5.
Electricity. the maximum deviation of an alternating current from its average value.
6.
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.
7.
Mathematics, argument ( def 8b ).

Origin:
1540–50; < Latin amplitūdō. See ample, -i-, -tude

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Based on the Random House Dictionary, © Random House, Inc. 2014.
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World English Dictionary
 amplitude (ˈæmplɪˌtjuːd) —n 1. greatness of extent; magnitude 2. abundance or copiousness 3. breadth or scope, as of the mind 4. astronomy the 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 5. maths Compare modulus See also Argand diagram Also called: argument (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 + iy is θ, that is, arctan y/x 6. physics the maximum variation from the zero or mean value of a periodically varying quantity [C16: from Latin amplitūdō breadth, from amplus spacious]

Collins English Dictionary - Complete & Unabridged 10th Edition
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Etymonline
Word Origin & History

amplitude
1540s, from L. amplitudinem (nom. amplitudo, gen. amplitudinis) "wide extent, width," from amplus (see ample). Amplitude modulation in ref. to radio wave broadcast (as opposed to frequency modulation) first attested 1921, usually abbreviated a.m.
Online Etymology Dictionary, © 2010 Douglas Harper
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American Heritage
Science Dictionary
 amplitude   (ām'plĭ-td')  Pronunciation Key  Physics One 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. Electronics The amount by which a voltage or current changes from zero or an average value.
The American Heritage® Science Dictionary
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American Heritage
Cultural Dictionary

### amplitude definition

In physics, the height of a crest (or the depth of a trough) of a wave.

The American Heritage® New Dictionary of Cultural Literacy, Third Edition
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Encyclopedia Britannica
Encyclopedia

amplitude

in physics, the maximum displacement or distance moved by a point on a vibrating body or wave measured from its equilibrium position. It is equal to one-half the length of the vibration path. The amplitude of a pendulum is thus one-half the distance that the bob traverses in moving from one side to the other. Waves are generated by vibrating sources, their amplitude being proportional to the amplitude of the source

Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
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Example sentences
The frequency of the sound is related to the mean grain size and the amplitude is controlled by the surface texture of the grains.
But the amplitude and timing of the wobble can reveal a planet's size as well as the shape of its orbit.
He does this by watching the waveform of the current flowing to each motor-a
product of its frequency and amplitude.
To stop the action, the operator lowers the amplitude below another trigger
threshold.
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