Definition of amplitude in English:

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Pronunciation: /ˈamplɪtjuːd/


[mass noun]
1 Physics The maximum extent of a vibration or oscillation, measured from the position of equilibrium: the amplitude of alpha rhythms [count noun]: waves with amplitudes greater than or equal to 20 mm
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  • Lifetimes and the ratio of initial amplitudes remained constant at all energies.
  • Vibrations and amplitudes are higher, giving heavier densities at a higher speed.
  • It keeps its shape, even at large amplitudes, because the speed of waves in the medium depends on frequency in just the right way.
1.1The maximum difference of an alternating electric current or potential from the average value: the detection of signals only a few microvolts in amplitude
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  • The correlation between changes in the kinetics of synaptic current and quantal amplitude remains strong for the corrected values as well.
  • Practical researchers are only too aware, however, that the optical output can frequently vary significantly in amplitude and spatial quality from point to point within a crystal.
  • Isochronal tail current amplitudes were normalized to the maximum amplitude obtained from that oocyte and plotted versus test potential.
2 Astronomy The angular distance of a celestial object from the true east or west point of the horizon at rising or setting.
Example sentences
  • In contrast, in a binary star system both components emit their own light, making possible much larger amplitudes in the variation of the total light received in our telescopes.
  • Finally, we evaluate the reliability of the amplitudes and phases determined in the initial study of the star's amplitude and frequency variability.
  • The star's amplitude is approximately 0.1 magnitude.
3Breadth, range, or magnitude: the amplitude of the crime of manslaughter lies beneath murder
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  • Past the half-mark, it morphs into a more ambitious and complex construction as the strings are given more scope and amplitude, but as they soon retract to the background, the original airy structure returns.
  • And also, given its magnitude, you know, the amplitude increases greatly with each point on the scale.
  • During these same thirty years or more, Sam has also become a writer of true amplitude: of outrage and forgiveness, of directness and intelligence, of tenderness and generosity.
4 Mathematics The angle between the real axis of an Argand diagram and a vector representing a complex number.
Example sentences
  • After covering the basics, he launches into a fairly academic discussion of signal and fourier analysis, and amplitude, angle and pulse modulation and demodulation.
  • A sine function has amplitude, phase, period and shift, and you can play tricks with these.
  • The amplitude of the observed dihedral angle distributions ascertains the flexibility of the secondary structure which never remains flat or adopts a reversed saddle shape.


Mid 16th century (in the senses 'physical extent' and 'grandeur'): from Latin amplitudo, from amplus 'large, abundant'.

For editors and proofreaders

Line breaks: amp¦li|tude

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