spectrum

English
The visible spectrum

Etymology

From Latin spectrum (“appearance, image, apparition”), from speciō (“look at, view”). Doublet of specter. See also scope.

Pronunciation
  • (Canada, UK) IPA(key): /ˈspektɹəm/
  • (US) IPA(key): /ˈspɛkt(ʃ)ɹəm/
  • Rhymes: -ɛktɹəm

Noun

spectrum (plural spectra or spectrums)

  1. A range; a continuous, infinite, one-dimensional set, possibly bounded by extremes.
    • 2012 November 7, Matt Bai, “Winning a Second Term, Obama Will Confront Familiar Headwinds”, in New York Times‎:
      As Mr. Obama prepared to take the oath, his approval rating touched a remarkable 70 percent in some polling — a reflection of good will across the political spectrum.
  2. Specifically, a range of colours representing light (electromagnetic radiation) of contiguous frequencies; hence electromagnetic spectrum, visible spectrum, ultraviolet spectrum, etc. [from later 17th c.]
    • 2010 October 30, Jim Giles, Jammed!, in New Scientist,
      Current 3G technologies can send roughly 1 bit of data - a one or a zero - per second over each 1 Hz of spectrum that the operator owns.
  3. (psychology, education) The autism spectrum.
  4. (chemistry) The pattern of absorption or emission of radiation produced by a substance when subjected to energy (radiation, heat, electricity, etc.).
  5. (mathematics, linear algebra) The set of eigenvalues of a matrix.
  6. (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.
  7. (abstract algebra, algebraic geometry) The set, denoted Spec(R), of all prime ideals of a given ring R, commonly augmented with a Zariski topology and considered as a topological space.
  8. (obsolete) Specter, apparition. [from early 17th c.]
  9. The image of something seen that persists after the eyes are closed.

Derived terms

Translations
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Anagrams

Dutch

Etymology

From Latin spectrum (“appearance, image, apparition”), from speciō (“look at, view”).

Pronunciation
  • Audio(file)

Noun

spectrum n (plural spectrums or spectra, diminutive spectrumpje n)

  1. spectrum

Derived terms

Latin

Etymology

From spec(iō) (“look at, behold”) +‎ -trum. Confer with speculum.

Pronunciation
  • (Classical) IPA(key): /ˈspek.trum/, [ˈspɛk.trũ]

Noun

spectrum n (genitive spectrī); second declension

  1. appearance, image
  2. apparition, specter

Inflection

Second declension.

Case Singular Plural
Nominative spectrum spectra
Genitive spectrī spectrōrum
Dative spectrō spectrīs
Accusative spectrum spectra
Ablative spectrō spectrīs
Vocative spectrum spectra

Descendants

References
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