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.

---

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

---

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

---

spectrum Cultural  

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

---

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

I fell somewhere in the middle of that spectrum.

From MarketWatch ● Oct. 16, 2026

But if our A.I. future winds up somewhere on the more dystopian end of the spectrum, won’t you want your guide through it to be a cute little guy?

From Slate ● Oct. 14, 2026

The FDA approval covers people with Alexander disease across the full age spectrum, from infancy through adulthood.

From Science Daily ● Oct. 13, 2026

The conglomerate has faced protests over industrial projects, scrutiny of its Indian telecom business during a spectrum allocation controversy, a high-profile dispute with Japan's Docomo and, more recently, questions over Air India's performance.

From BBC ● Oct. 12, 2026

New York was another spectrum unto itself, and the great diversity I’d seen at Howard, solely among black people, now spread across a metropolis.

From "Between the World and Me" by Ta-Nehisi Coates

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

Their UV spectra contain fingerprints of chemical elements in their atmospheres while also revealing details about the stellar winds carrying material away from their surfaces.

From Science Daily ● Sep. 24, 2026

For the first time, DR20 includes SDSS-V stellar and extra-galactic optical spectra obtained in the Southern Hemisphere.

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

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

It's clear that coming out is still a complicated process despite Gen Z's more widespread understanding and acceptance of the gender and sexuality spectrums.

From Salon ● Aug. 15, 2023

Color perception is also influenced by culture—various cultural groups and languages describe hues in very different spectrums.

From Scientific American ● Jul. 21, 2023

Like “Lioness,” both the “Avatar” movies and the Marvel films are also about war and the spectrums of “good” and “evil.”

From Los Angeles Times ● Jul. 18, 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

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

From "The Belles" by Dhonielle Clayton

Random Word

Spin the wheel and learn a new word!

---

Related Words

• continuum
• range
• sphere

---