Meaning

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

originEtymology tree Proto-Indo-European *speḱ- Proto-Indo-European *-yeti Proto-Indo-European *spéḱyeti Proto-Italic *spekjō Latin speciō Proto-Indo-European *-tḗr Proto-Indo-European *-trom Proto-Italic *-trom Latin -trum Latin spectrumbor. English spectrum From Latin spectrum (“appearance, image, apparition”), from speciō (“look at, view”). Doublet of specter. See also scope.

Etymology from Wiktionary, CC BY-SA 3.0