Definition of spectrum in English:

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Pronunciation: /ˈspɛktrəm/

noun (plural spectra /ˈspɛktrə/ or spectrums)

1A band of colours, as seen in a rainbow, produced by separation of the components of light by their different degrees of refraction according to wavelength.
Example sentences
  • If viewed through a prism, however, there is a decomposition of the light into the colors of the spectrum, each with different wavelengths.
  • He has used the spectrum of colours in the rainbow effectively to create an atmosphere of calm.
  • He is shown seated before his famous invention: a ruling machine for producing concave diffraction gratings, which are slightly curved metal plates scored with minutely spaced lines that diffract light into spectra.
1.1 (the spectrum) The entire range of wavelengths of electromagnetic radiation.
Example sentences
  • Light, the diet of eyes, constitutes a tiny part of the entire spectrum of electromagnetic radiation.
  • In the meantime over twenty presentations internationally have moved to show that across the spectrum electromagnetic fields are genotoxic, that is they damage DNA.
  • But apricot can add a spring-like touch as well, since it falls more in the yellow-orange range of the spectrum.
1.2A characteristic series of frequencies of electromagnetic radiation emitted or absorbed by a substance.
Example sentences
  • The adsorption and emission of spectra characteristic of atoms also suggested that they were due to the oscillations of charged particles on the atomic or sub-atomic scale.
  • One method they use, fluorescence spectroscopy, involves recording optical spectra from molecules absorbing and emitting light.
  • It should be noted that immunoglobulins often can be found throughout the electrophoretic spectrum.
1.3The components of a sound or other phenomenon arranged according to such characteristics as frequency, charge, and energy.
Example sentences
  • The properties ascribed to electrons, for instance, such as their charge and half-integral spin, were themselves responses to quite specific experimental findings involving discharge tube phenomena and spectra.
  • The height of the spectrum indicates the extent of that frequency's contribution to the variance of the growth rate.
  • Radio spectrum can also be mapped in other ways, onto territory.
2Used to classify something in terms of its position on a scale between two extreme points: the left or the right of the political spectrum
More example sentences
  • Modern biology has come to occupy an extreme position in the spectrum of the sciences, dominated by historical explanations of the evolutionary adventures of genes.
  • But, largely thanks to the Blairite project, the gap that separates the Tories and Labour has dramatically moved its position on the political spectrum.
  • If Churchill is so violently attacked by both extremes of the political spectrum, we can assume that he cannot have been that bad.
2.1A wide range: self-help books are covering a broader and broader spectrum
More example sentences
  • The budding writers touched upon a wide spectrum of issues ranging from suspense, fantasy, ghosts, sporting rivalry to philosophy and science fiction.
  • You've seen their work in a wide spectrum of venues ranging from Fast Forward to Time magazine, and now you can see it in person.
  • Economic geography supposedly has a wide spectrum of subjects, ranging from agrarian and pastoral economies to resource utilization and changes in land use.
range, gamut, sweep, scope, span;
compass, orbit, ambit


Early 17th century (in the sense 'spectre'): from Latin, literally 'image, apparition', from specere 'to look'.

Words that rhyme with spectrum


For editors and proofreaders

Line breaks: spec|trum

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