spectrum

[spek-truhm]

noun

plural

spectra, spectrums 

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.

spectrum

/ 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

plural

spectra 

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

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

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.

Word History and Origins

Origin of spectrum¹

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

Word History and Origins

Origin of spectrum¹

C17: from Latin: appearance, image, from spectāre to observe, from specere to look at

Idioms and Phrases

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.

Example Sentences

“Summer,” in full bloom, offers bursts of pink and orange while a spectrum of greens sets the stage for the vernal bounty.

Read more on The Wall Street Journal

The diverging experience of consumers at the top and the bottom of the wealth spectrum is being referred to as a K-shaped economy.

Read more on The Wall Street Journal

These country megastars have come to define opposite poles of the genre’s spectrum.

Read more on The Wall Street Journal

“Studies have shown that there is no link between receiving vaccines and developing autism spectrum disorder ... No links have been found between any vaccine ingredients and ASD.”

Read more on Los Angeles Times

At the opposite end of the spectrum that runs from cozy to hair-raising were two immersive fiction features about military disasters that hit devastatingly.

Read more on The Wall Street Journal

Related Words

• continuum 
• range 
• sphere