spectrum

Etymology
From, from. . See also.

Noun

 * 1) A range; a continuous, infinite, one-dimensional set, possibly bounded by extremes.
 * 2) Specifically, a range of colours representing light (electromagnetic radiation) of contiguous frequencies; hence electromagnetic spectrum, visible spectrum, ultraviolet spectrum, etc.
 * 3)  The autism spectrum.
 * 4) (chemistry) The pattern of absorption or emission of radiation produced by a substance when subjected to energy (radiation, heat, electricity, etc.).
 * 5)  The set of eigenvalues of a matrix.
 * 6)  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.
 * 7)  An abstract object in mathematics created from a commutative ring $$R$$ and denoted $$\operatorname{Spec}(R)$$ or $$\operatorname{Spec} R$$ and said to be the spectrum of $$R$$; useful in the study of such rings for providing a geometric object which encodes many of the properties $$R$$, and in modern geometry for  generalizing the notion of an algebraic variety to that of an affine scheme. Formally, the set of all prime ideals $$R$$ equipped with the Zariski topology and augmented with a sheaf of rings called the structure sheaf, generated by the B-sheaf on the distinguished open sets $$D_f$$ which assigns the localization of $$R$$ at $$f$$ to each set $$D_f$$, regarded as a ring of functions on $$D_f$$. See
 * 8)  Specter, apparition.
 * 9) The image of something seen that persists after the eyes are closed.
 * 1)  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.
 * 2)  An abstract object in mathematics created from a commutative ring $$R$$ and denoted $$\operatorname{Spec}(R)$$ or $$\operatorname{Spec} R$$ and said to be the spectrum of $$R$$; useful in the study of such rings for providing a geometric object which encodes many of the properties $$R$$, and in modern geometry for  generalizing the notion of an algebraic variety to that of an affine scheme. Formally, the set of all prime ideals $$R$$ equipped with the Zariski topology and augmented with a sheaf of rings called the structure sheaf, generated by the B-sheaf on the distinguished open sets $$D_f$$ which assigns the localization of $$R$$ at $$f$$ to each set $$D_f$$, regarded as a ring of functions on $$D_f$$. See
 * 3)  Specter, apparition.
 * 4) The image of something seen that persists after the eyes are closed.
 * 1)  Specter, apparition.
 * 2) The image of something seen that persists after the eyes are closed.

Translations

 * Belarusian: спектр
 * Bulgarian:
 * Chinese:
 * Mandarin:
 * Finnish:
 * French:
 * Georgian: სპექტრი
 * Greek:
 * Irish: speictream
 * Italian:
 * Japanese:
 * Korean:
 * Persian:
 * Polish:
 * Portuguese:, espetro
 * Romanian:
 * Russian: ,
 * Spanish:
 * Tagalog:
 * Thai: สเปกตรัม
 * Ukrainian: спектр


 * Afrikaans: spektrum
 * Albanian: spektri
 * Arabic: طَيْف
 * Armenian:
 * Basque: espektro
 * Bulgarian:
 * Catalan:
 * Chinese:
 * Cantonese: 光譜
 * Hakka: 光譜
 * Mandarin:
 * Czech: spektrum
 * Danish: spektrum, spekter
 * Dutch:
 * Esperanto: spektro
 * Estonian: spekter
 * Finnish: ,
 * French:
 * Galician:
 * Georgian: სპექტრი
 * German:
 * Greek:, φωτόφασμα
 * Hebrew:
 * Hungarian: ,
 * Irish: speictream
 * Italian:
 * Japanese: ,
 * Korean:
 * Kurdish:
 * Northern Kurdish:
 * Latvian: spektrs
 * Lithuanian: spektras
 * Macedonian: спектар
 * Maori: tūāwhiorangi
 * Norwegian:
 * Bokmål: spektrum, spekter
 * Nynorsk: spektrum, spekter
 * Persian: ,
 * Polish:
 * Portuguese:, espetro
 * Romanian:
 * Russian:
 * Serbo-Croatian:
 * Cyrillic: спектар
 * Roman:
 * Slovak: spektrum
 * Slovene:
 * Spanish:
 * Swedish:
 * Tagalog:
 * Telugu:
 * Thai: สเปกตรัม
 * Turkish:
 * Ukrainian: спектр
 * Vietnamese: (光譜)
 * Volapük:, kölaspäktrum


 * Chinese:
 * Mandarin:
 * Spanish:


 * Finnish:
 * French:
 * German:
 * Greek:
 * Irish: speictream
 * Japanese:
 * Khmer: ស្ប៊ិច
 * Maori: tūāwhiorangi
 * Persian:
 * Portuguese:, espetro


 * Finnish:
 * French:
 * German:
 * Greek:
 * Irish: speictream
 * Italian:
 * Japanese:
 * Portuguese:, espetro
 * Romanian:
 * Russian:


 * German: (1, 2, 3)
 * Swedish: (2, 3)

Etymology
From, from.

Etymology
From (making it a doublet of ).

The only attestation in Classical antiquity is in a pair of letters between Cicero and Cassius Longinus which imply that the Epicurean Catius (fl. c. 50s–40s BC) used spectrum as a translation of the Greek philosophical term. It may therefore have been coined by Catius as a neologism, although alternatively, it could be an undocumented but preexisting word that he repurposed as a technical term.

After Cicero, the word is extremely sparsely attested until being revived around the start of the sixteenth century by Renaissance humanist authors with the meaning "apparition" or "phantom", possibly influenced by the fact that Greek εἴδωλον also had this sense.

The scientific use to refer to the visible spectrum of colored light was first introduced by Isaac Newton, who used the word in the second half of the seventeenth century in both his English writings and in his first Latin draft of the Opticks, the Fundamentum Opticae, although the 1706 Latin translation of Opticks by Samuel Clarke translates Newton's English spectrum into Latin as imago.

Noun

 * 1) appearance, image
 * 2) apparition, specter, phantom
 * 3)  spectrum (band of light arranged in order by wavelength)
 * 1)  spectrum (band of light arranged in order by wavelength)
 * 1)  spectrum (band of light arranged in order by wavelength)