spectrum

/ˈspɛktrəm/

/ˈspɛktrəm/

Other forms: spectra; spectrums

A spectrum is a broad range of similar things or qualities, like the wide spectrum of political beliefs in this country, ranging anywhere from super conservative to über-liberal and everything in between.

Our modern definition of spectrum started out in the 1600s, when scientists used it to refer to the band of colors formed by a beam of light, like a rainbow. In physics, it’s a word that describes the distribution of something, like energy or atomic particles. We still use those scientific meanings today, but spectrum can also apply to non-science related groupings or ranges of related things.

Definitions of spectrum

1. noun

   a broad range of related objects, values, qualities, ideas, or activities
   type of:

   ambit, compass, orbit, range, reach, scope

   an area in which something acts or operates or has power or control: "the range of a supersonic jet"
2. noun

   an ordered array of the components of an emission or wave
   types:

   absorption spectrum

   the spectrum of electromagnetic radiation that has passed through a medium that absorbed radiation of certain wavelengths

   action spectrum

   the efficiency with which electromagnetic radiation produces a photochemical reaction plotted as a function of the wavelength of the radiation

   atomic spectrum

   (physics) a spectrum of radiation caused by electron transitions within an atom; the series of spectrum lines is characteristic of the element

   electromagnetic spectrum

   the entire frequency range of electromagnetic waves

   emission spectrum

   spectrum of electromagnetic radiation emitted by a self-luminous source

   infrared spectrum

   the spectrum of infrared radiation

   line spectrum

   a spectrum in which energy is concentrated at particular wavelengths; produced by excited atoms and ions as they fall back to a lower energy level

   mass spectrum

   a distribution of ions as shown by a mass spectrograph or a mass spectrometer

   microwave spectrum

   the part of the electromagnetic spectrum corresponding to microwaves

   radio spectrum, radio-frequency spectrum

   the entire spectrum of electromagnetic frequencies used for communications; includes frequencies used for radio and radar and television

   acoustic spectrum, sound spectrum

   the distribution of energy as a function of frequency for a particular sound source

   ultraviolet spectrum

   the spectrum of ultraviolet radiation

   color spectrum, visible spectrum

   the distribution of colors produced when light is dispersed by a prism

   speech spectrum

   the average sound spectrum for the human voice

   type of:

   array

   an orderly arrangement