- 1a band of colored lights in order of their wavelengths, as seen in a rainbow and into which light may be separated A spectrum is formed by a ray of light passing through a prism. Red and violet are at opposite ends of the spectrum.
- 2 a range of sound waves or several other types of waves the electromagnetic/radio/sound spectrum
- 3 [usually singular] a complete or wide range of related qualities, ideas, etc. a broad spectrum of interests We will hear views from across the political spectrum.