Other forms: spectra, spectrums
A spectrum is the full rainbow of light spread out from red to violet — or any full range. The visible spectrum, across the spectrum, a broad spectrum.
Splitting light this way shows what a thing is made of, because each element absorbs its own set of wavelengths — which is how we know what stars are. The figurative sense means a continuous range rather than fixed categories. The Latin means an appearance.
1nounspectrumThe band of colours light spreads into.
“A prism splits white light into the colours of the spectrum.”
2nouncontinuousA continuous range of anything.
“The new party attracts voters from across the political spectrum.”
spectrum is a range.
Latin spectrum means an appearance or image, from specere, to look at. Spectre is the same word.
Latin
spectrum
English, today
spectrum
Built from
Borrowed from Latin spectrum. From Latin spectrum (“appearance, image, apparition”), from speciō (“look at, view”). a doublet of specter. See also scope.
Etymology from Wiktionary, CC BY-SA