spectrum Meaning, Definition & Usage

noun an ordered array of the components of an emission or wave
noun a broad range of related objects or values or qualities or ideas or activities

L. See Specter.

plural Spectra

An apparition; a specter. Obs.
(Opt.) (a) The several colored and other rays of which light is composed, separated by the refraction of a prism or other means, and observed or studied either as spread out on a screen, by direct vision, by photography, or otherwise. See Illust. of Light, and Spectroscope. (b) A luminous appearance, or an image seen after the eye has been exposed to an intense light or a strongly illuminated object. When the object is colored, the image appears of the complementary color, as a green image seen after viewing a red wafer lying on white paper. Called also ocular spectrum.