Spectrum definition

spĕktrəm
spectra spectrums
See word origin
Frequency:
The intensity of any radiation or motion displayed as a function of frequency, or wavelength.
noun
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Spectrum is the range of colors of wavelength energy sent out from a light source when viewed through a prism.

An example of a spectrum is a rainbow.

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A continuous range or the entire extent.

A wide spectrum of opinion.

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An afterimage.
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The observed distribution of a phenomenon across a range of measurement.
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Spectrum is a broad range of related ideas, qualities or activities.

An example of a spectrum is a group of activities used for teaching someone how to play basketball.

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A range of radio frequencies assigned by a regulatory agency for use by a given group or organization.
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The entire range over which some measurable property of a physical system or phenomenon can vary, such as the frequency of sound, the wavelength of electromagnetic radiation, or the mass of specific kinds of particles.
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A graphic or photographic representation of such a measurable range; a spectrogram.
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A range of values of a quantity or set of related quantities.
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A broad sequence or range of related qualities, ideas, or activities.

The whole spectrum of 20th-century thought.

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The entire range over which some measurable property of a physical system or phenomenon can vary, such as the frequency of sound, the wavelength of electromagnetic radiation, or the mass of specific kinds of particles.
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A specific portion of such a range.

The infrared spectrum.

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A characteristic distribution of phenomena manifested over such a range.

The emission spectrum for sodium vapor.

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A band of colors produced when the wavelengths making up white light are separated, as when light passes through a prism or strikes drops of water.
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A range of values of a quantity or set of related quantities.

The income spectrum.

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A sequence or range of related qualities, ideas, activities, entities, or phenomena.

The whole spectrum of 20th-century thought; the spectrum of genes involved in the immune response.

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Generally referring to frequency spectrum. See electromagnetic spectrum.
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Specter, apparition. [from early 17th c.]
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A range; a continuous, infinite, one-dimensional set, possibly bounded by extremes.
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Specifically, a range of colours representing light (electromagnetic radiation) of contiguous frequencies; hence electromagnetic spectrum, visible spectrum, ultraviolet spectrum, etc. [from later 17th c.]
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(chemistry) The pattern of absorption or emission of radiation produced by a substance when subjected to energy (radiation, heat, electricity, etc.).
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(mathematics, linear algebra) The set of eigenvalues of a matrix.
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(mathematics, functional analysis) Of a bounded linear operator A, the set of scalar values λ such that the operator A"”λI, where I denotes the identity operator, does not have a bounded inverse; intended as a generalisation of the linear algebra sense.
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The series of colored bands or lines dispersed and arranged in the order of their respective wavelengths by the passage of white light through a prism or other dispersing device and shading continuously from red (produced by the longest wave visible) through violet (produced by the shortest): the six main colors of the spectrum are red, orange, yellow, green, blue, and violet, with a seventh color (indigo) sometimes specified, between blue and violet.
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A graphic representation of such a distribution; a spectrogram.
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A range over which some measurable property of a physical phenomenon, such as the frequency of sound or electromagnetic radiation, or the mass of specific kinds of particles, can vary. For example, the spectrum of visible light is the range of electromagnetic radiation with frequencies between between 4.7 × 1014 and 7.5 × 1014 hertz.
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on the spectrum
  • having a diagnosis based on a wide range of related symptoms including those of autism and Asperger's syndrome
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Other Word Forms

Noun

Singular:
spectrum
Plural:
spectra, spectrums

Idioms and Phrasal Verbs

Origin of spectrum

  • Latin appearance from specere to look at spek- in Indo-European roots

    From American Heritage Dictionary of the English Language, 5th Edition

  • From Latin spectrum (“appearance, image, apparition"), from speciō (“look at, view"). (see scope)

    From Wiktionary

Spectrum Sentence Examples

  • Our eyes are capable of seeing only a narrow spectrum of light.

  • There is a certain amount of evidence that at any rate in some cases light is necessary, and that the violet rays of the spectrum are chiefly concerned.

  • Let AoBo be a plane wave-surface of the light before it falls upon the prisms, AB the corresponding wave-surface for a particular part of the spectrum after the light has passed the prisms, or after it has passed the eye-piece of the observing telescope.

  • There are many thousands of lines in the mercury spectrum, so that from this evidence it would appear that for mercury vapour n ought to be very great, and y almost equal to unity.

  • Moseley, shortly after the discovery of the diffraction of X-rays by crystals, set to work to examine the X-ray spectrum of a number of elements each of which he made in turn the target of an X-ray tube.

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Also Mentioned In

Words near spectrum in the Dictionary