spectrum

noun

spec·​trum ˈspek-trəm 

plural spectra ˈspek-trə  or spectrums

1

a

: a continuum of color formed when a beam of white light is dispersed (as by passage through a prism) so that its component wavelengths are arranged in order

b

: any of various continua that resemble a color spectrum in consisting of an ordered arrangement by a particular characteristic (such as frequency or energy): such as

(1)

: electromagnetic spectrum

(2)

: radio spectrum

(3)

: the range of frequencies of sound waves

(4)

: mass spectrum

c

: the representation (such as a plot) of a spectrum

2

a

: a continuous sequence or range

a wide spectrum of interests

opposite ends of the political spectrum

b

: kinds of organisms associated with a particular situation (such as an environment)

c

: a range of effectiveness against pathogenic organisms

an antibiotic with a broad spectrum

see also:

on the spectrum

Synonyms of spectrum

• range
• scale
• gamut

Examples of spectrum in a Sentence

beautiful scarves in all the colors of the spectrum

the complete spectrum of opinions on this hotly debated subject

Recent Examples on the Web

No police necessity can explain their excessive use of force, which has shocked and disgusted fair-minded people across the political spectrum. —Tim Dunn, Boston Herald, 6 Apr. 2026

At the other end of the spectrum are Josh Lowe (46%), Jorge Soler (42%) and Oswald Peraza (39%). —Jeff Fletcher, Oc Register, 5 Apr. 2026

Across the price spectrum, retailers are struggling to maintain margins as costs rise and consumers become increasingly price sensitive amid inflationary pressures. —Elsa Ohlen, CNBC, 5 Apr. 2026

At the other end of the spectrum, Nicholas Hoult subtly flexed a rose-gold Jaeger-LeCoultre Reverso with an elegant Milanese bracelet courtside at a Lakers game and John Mulaney rocked the rare Gérald Genta Geneva Minute Repeater on the streets of New York. —Rachel Cormack, Robb Report, 4 Apr. 2026

Word History

Etymology

New Latin, from Latin, appearance — more at specter

First Known Use

1672, in the meaning defined at sense 1a

Phrases Containing spectrum

• a broad spectrum
• absorption spectrum
• autism spectrum disorder
• autistic spectrum disorder
• broad-spectrum
• electromagnetic spectrum
• mass spectrum
• on the spectrum
• radio spectrum

Rhymes for spectrum

• electrum

Kids Definition

spectrum

noun

spec·​trum ˈspek-trəm 

plural spectra -trə  or spectrums

1

a

: the group of different colors including red, orange, yellow, green, blue, indigo, and violet arranged in the order of their wavelengths and seen when white light passes through a prism and falls on a surface or when sunlight is scattered by water droplets to form a rainbow

b

: electromagnetic spectrum

2

: a continuous range or series

a wide spectrum of interests

Medical Definition

spectrum

noun

spec·​trum ˈspek-trəm 

plural spectra -trə  or spectrums

1

a

: a continuum of color formed when a beam of white light is dispersed (as by passage through a prism) so that its component wavelengths are arranged in order

b

: any of various continua that resemble a spectrum in consisting of an ordered arrangement by a particular characteristic (as frequency or energy): as

(1)

: electromagnetic spectrum

(2)

: mass spectrum

c

: the representation (as a plot) of a spectrum

2

: a continuous sequence or range

specifically : a range of effectiveness against pathogenic organisms see broad-spectrum, narrow-spectrum