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

Tributes have poured in from US presidents across the political spectrum and musicians across all genres, remembering her not just for her award-winning career, but her philanthropy and humble nature that transcended country music.

From BBC ● Aug. 26, 2026

“I recognize both sides of the political spectrum and very much just consider myself to be a free thinker, someone who is continuously seeking the truth wherever that truth may come from,” Amor said.

From Salon ● Aug. 26, 2026

The Canadian leader has drawn support from across the political spectrum in Canada for ditching what some premiers and industry groups feared was a bad deal with the U.S.

From The Wall Street Journal ● Aug. 26, 2026

"These two tissue-resident natural killer cell populations look very similar, and they have some of the same requirements, but their function seems to be on opposite ends of the spectrum," Sunwoo said.

From Science Daily ● Aug. 25, 2026

The different wavelengths of light are what the human eye sees as different colors, with the longest wavelengths appearing at the red end of the spectrum and the shortest wavelengths at the blue end.

From "A Brief History of Time: And Other Essays" by Stephen Hawking

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

From Science Daily ● Aug. 14, 2026

DR20 now includes integral field spectroscopy maps of 6 separate target regions covering 169 tiles and about 300,000 spectra.

From Science Daily ● Aug. 14, 2026

Roughly 99% of those objects will be observed only photometrically, meaning through images taken in different colors rather than detailed spectra.

From Science Daily ● Jun. 29, 2026

By examining highly precise data collected by DAMPE, researchers discovered a universal pattern in the energy spectra of primary cosmic ray nuclei, ranging from lightweight protons to much heavier iron nuclei.

From Science Daily ● May 14, 2026

In analyzing these spectra, O. B. Toon, J. B. Pollack and I found that certain features seem best accounted for by montmorillonite and other kinds of clay.

From "Cosmos" by Carl Sagan

In the last 15 years or so, psychiatry has embraced what’s called a dimensional approach, based on the idea of scales and spectrums of trait and symptom severity.

From Scientific American ● Jul. 24, 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

I’m a world traveler and appreciate the differences in culture across all spectrums.

From Los Angeles Times ● Dec. 29, 2021

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