Definition of amplitude in English:


Line breaks: amp¦li|tude
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.
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    • 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.
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    • 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'.

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