spectrum

Fetched 2026-10-26 (cache).

Synonyms: spektrum, spectre, spectral, speculum, electrum, spectred, spectrous, spectres, spetum, plectrum, spectra

Antonyms: spektrum, spectre, spectral, speculum, electrum, spectred, spectrous, spectres, spetum, plectrum, spectra

Related words from Datamuse; suggestions, not definitions.

Noun

1. A [[range]]; a [[continuous]], [[infinite]], [[one-dimensional]] set, possibly bounded by [[extremes]].
2. Specifically, a range of [[colour]]s representing [[light]] ([[electromagnetic radiation]]) of contiguous [[frequency|frequencies]]; hence [[electromagnetic spectrum]], [[visible spectrum]], [[ultraviolet]] spectrum, etc. {{defdate|from later 17th c.}}
3. {{lb|en|psychology|education|usually with '''the'''}} The [[autism spectrum]].
4. {{lb|en|telecommunications}} A set of frequencies that are used for radio-frequency communication; not necessarily a continuous range.
5. {{lb|en|chemistry}} The pattern of [[absorption]] or [[emission]] of [[radiation]] produced by a substance when subjected to energy (radiation, heat, electricity, etc.).
6. {{lb|en|mathematics|linear algebra}} The set of [[eigenvalue]]s of a [[matrix]].
7. {{lb|en|mathematics|functional analysis}} Of a [[bounded]] [[linear operator]] ''A'', the set of [[scalar]] values λ such that the [[operator]] ''A—λI'', where ''I'' denotes the identity operator, does not have a bounded [[inverse]]; intended as a generalisation of the linear algebra sense.
8. {{lb|en|obsolete}} [[specter|Specter]], [[apparition]]. {{defdate|from early 17th c.}}
9. The [[image]] of something [[see]]n that persists after the [[eye]]s are [[close]]d.

Source: Wiktionary · CC BY-SA 4.0 (Wiktionary dump) · cached copy, not a rewrite.