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

But it’s especially resonant right now, when voters across the spectrum are increasingly fed up with the country’s existing leadership.

From Salon

She sees style as a spectrum rather than a hierarchy of good and bad.

From BBC

It is a spectrum, meaning it includes a wide range of traits or characteristics which vary from person to person.

From BBC

Badenoch's signals on climate change, on leaving the European Convention on Human Rights, tip towards the right of the Conservative spectrum, on territory that right now, Reform have painted in bold primary colours.

From BBC

Leaders from across the political spectrum have condemned the attack.

From BBC

Related Words

• continuum 
• range 
• sphere