• Spectrum

    Pronunciation

    • Canada IPA: /ˈspektrəm/
    • US IPA: /ˈspɛkt(ʃ)ɹəm/
    • Rhymes: -ɛktrəm

    Origin

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

    Full definition of spectrum

    Noun

    spectrum

    (plural spectra or spectrums)
    1. Specter, apparition. from early 17th c.
    2. A range; a continuous, infinite, one-dimensional set, possibly bounded by extremes.
    3. 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.
    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.

    Related terms

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