What does spectrum mean?
A spectrum is a range of related frequencies, qualities, or possibilities. In its scientific sense, it most often describes the distribution of electromagnetic radiation across wavelengths, as in the visible spectrum of light, which includes the colors from red through violet. In everyday and social contexts, the word extends to any broad range of ideas, emotions, experiences, or types of behavior: a spectrum of political opinion, for example, suggests that opinion varies continuously between different positions. The phrase “spectrum of” is especially common when discussing diversity, variation, or the full range of something. The word can also refer to a range of numerical values, particularly in technical and statistical contexts. Its familiar scientific association gives the general figurative use an impression of breadth and systematic variation.
nounThe range of different wavelengths or frequencies of electromagnetic radiation, especially visible light. By extension, the word refers to a continuous range or broad variety of qualities, ideas, emotions, or types of something.
- A range of wavelengths or frequencies of electromagnetic radiation, especially the series of colors visible in light.
- A continuous range of similar qualities, ideas, emotions, or types of something.
- A range of numerical values, especially a distribution shown on a graph or in a statistical analysis.
"The prism separated the sunlight into a full spectrum of colors."
"The exhibition covered the entire spectrum of contemporary photography."
"Researchers analyzed the spectrum of frequencies emitted by the device."
The standard plural is spectra. The form spectrums is also used in some technical contexts, but spectra is preferred in scientific and general usage.
"The spectra reveal differences in the chemical composition of the samples."
A prism reveals the hidden rainbow in ordinary white light by separating it into its component colors.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does spectrum come from?
Spectrum comes from Latin spectrum, meaning “image” or “appearance,” a usage connected with seeing and with the appearance of colors. The word entered English in the early 17th century, initially in optics, where it referred to the band of colors produced when light passed through a prism. Its later figurative sense developed from the idea of a range or graduated sequence. The Latin root is also reflected in cognates such as spectator, speculate, inspect, and circumstance.
Related word forms
How spectrum is actually used
In general use, the word often suggests a broad, continuous range rather than merely a collection. In physics and astronomy, it has a more technical meaning, referring specifically to a distribution of radiation or energy across frequencies or wavelengths.
Easily confused with spectrum
A spectrum is a range of frequencies, colors, or qualities, whereas a specter is a ghostly apparition.
A spectrum is a range or distribution, while a speculum is a mirror or a medical instrument used for examination.