spectrum

American  

[spek-truhm] / ˈspɛk trəm /

noun

• spectra,
  plural
• spectrums
  plural

1. Physics.

   1. an array of entities, as light waves or particles, ordered in accordance with the magnitudes of a common physical property, as wavelength or mass: often the band of colors produced when sunlight is passed through a prism, comprising red, orange, yellow, green, blue, indigo, and violet.

   2. this band or series of colors together with extensions at the ends that are not visible to the eye, but that can be studied by means of photography, heat effects, etc., and that are produced by the dispersion of radiant energy other than ordinary light rays.

2. a broad range of varied but related ideas or objects, the individual features of which tend to overlap so as to form a continuous series or sequence.

   the spectrum of political beliefs.

3. the range of traits and behaviors that are considered to be characteristic of autism spectrum disorder.

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idioms

1. on the spectrum, having an autism spectrum disorder, or displaying behaviors considered characteristic of those disorders.

   The nonprofit works to increase public awareness about the day-to-day issues faced by people on the spectrum.

spectrum British  

/ ˈspɛktrəm /

noun

1. the distribution of colours produced when white light is dispersed by a prism or diffraction grating. There is a continuous change in wavelength from red, the longest wavelength, to violet, the shortest. Seven colours are usually distinguished: violet, indigo, blue, green, yellow, orange, and red

2. the whole range of electromagnetic radiation with respect to its wavelength or frequency

3. any particular distribution of electromagnetic radiation often showing lines or bands characteristic of the substance emitting the radiation or absorbing it See also absorption spectrum emission spectrum

4. any similar distribution or record of the energies, velocities, masses, etc, of atoms, ions, electrons, etc

   a mass spectrum

5. any range or scale, as of capabilities, emotions, or moods

6. another name for an afterimage

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spectrum Scientific  

/ spĕk′trəm /

• spectra
  plural

1. 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 × 10 ¹⁴ and 7.5 × 10 ¹⁴ hertz.

2. The observed distribution of a phenomenon across a range of measurement.

3. See more at atomic spectrum spectroscopy

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spectrum Cultural  

1. The range of wavelengths characteristic of a specific type of radiation.

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Discover More

The spectrum making up visible light contains light in the colors violet, indigo, blue, green, yellow, orange, and red, with violet having the shortest wavelength and highest frequency, and red having the longest wavelength and lowest frequency.

Other Word Forms

Noun Inflected Forms

• spectra
  plural
• spectrums
  plural

Etymology

Origin of spectrum

First recorded in 1605–15; from Latin: “appearance, form,” equivalent to spec(ere) “to look at, regard” + -trum instrumental noun suffix

Explanation

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.

Example Sentences

See Examples For:

spectrum spectra spectrums

All of these behaviors occur on a spectrum, and not all are at play in every estrangement, Scharp says.

From The Wall Street Journal ● Oct. 10, 2026

The company has reached a deal to buy cellular spectrum licenses from investment firm Grain Management, its biggest move yet into a wireless market dominated by traditional telecom companies, The Wall Street Journal reports.

From The Wall Street Journal ● Oct. 9, 2026

Acquiring Grain Management’s 800 MHz spectrum gives Starlink’s mobile ambitions a major boost, providing the groundwork for cellular networks.

From MarketWatch ● Oct. 9, 2026

But it still needs final security clearances and spectrum allocation before it can begin commercial services.

From BBC ● Oct. 9, 2026

But because of the limitations of our eyes, we have a prejudice, a bias, toward that tiny rainbow band we call the spectrum of visible light.

From "Cosmos" by Carl Sagan

Scientists expect to release images and spectra from some of Juice's instruments in the coming weeks, once the data have reached Earth and instrument teams have had time to evaluate them.

From Science Daily ● Oct. 3, 2026

Across the BHM and MWM surveys, DR20 contains more than 3 million spectra covering 1.5 million stars.

From Science Daily ● Aug. 14, 2026

The spectra of Larissa, Galatea, and Neptune's rings contained signs of magnesium-rich phyllosilicates.

From Science Daily ● Aug. 14, 2026

One interesting result, Davis says, is that signatures of magnesium-rich phyllosilicates were found in the spectra of Larissa, Galatea, and the rings -- minerals that only form in the presence of liquid water.

From Science Daily ● Aug. 14, 2026

Following a lead by the astronomer V. M. Slipher at Lowell Observatory, they began measuring the spectra of distant galaxies.

From "Cosmos" by Carl Sagan

Explain to me why they're important for us to get clarity on, within those spectrums.

From Salon ● Aug. 20, 2023

“These surveys tend to include much broader spectrums of trans individuals, and we cannot be as certain that our results are as problematic in the broader group,” Dr. Frisch said.

From New York Times ● Jun. 27, 2023

“I’m questioning whether it is. … The Pride flag represents making space for all humans on all the spectrums, and this is where we’re going as a human species,” Cain said.

From Seattle Times ● Jun. 14, 2023

Thermal emission spectrums of the planet’s daylight side will be compared to known rocks like basalt and granite to see if they can deduce a surface composition.

From Scientific American ● Jun. 3, 2022

While the other mothers forced my sisters to trace their cursive letters, I worked on shades and spectrums.

From "The Belles" by Dhonielle Clayton

Related Words

• continuum
• range
• sphere