- spectrum
- 1611, "apparition, specter," from L. spectrum "appearance, image, apparition," from specere "to look at, view" (see scope (1)). Meaning "band of colors formed from a beam of light" first recorded 1671. Spectroscope (1861) is a hybrid, with Gk. -skopion, from skopein "to look at, examine," which is from the same PIE root as spectrum.