spectrum
/ˈspɛktɹəm/ noun
Forms spectra spectrums
- noun A range; a continuous, infinite, one-dimensional set, possibly bounded by extremes.
- noun Specifically, a range of colours representing light (electromagnetic radiation) of contiguous frequencies; hence electromagnetic spectrum, visible spectrum, ultraviolet spectrum, etc.
- noun (psychology, education, usually with the) The autism spectrum.
- noun (telecommunications) A set of frequencies that are used for radio-frequency communication; not necessarily a continuous range.
- noun (chemistry) The pattern of absorption or emission of radiation produced by a substance when subjected to energy (radiation, heat, electricity, etc.).
- noun (mathematics, linear algebra) The set of eigenvalues of a matrix.
- noun (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.
- noun (commutative algebra, algebraic geometry) An abstract object in mathematics created from a commutative ring R and denoted operatorname Spec(R) or operatorname SpecR 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 Spectrum of a ring on Wikipedia.Wikipedia
Synonyms
Etymology
From Latin spectrum (“appearance, image, apparition”), from speciō (“look at, view”). Doublet of specter. See also scope.
Webster’s 1913
- noun An apparition; a specter. [Obs.]
- noun (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.
Etymology [L. See Specter.]
Sources: Wiktionary · Webster’s 1913 — from the Wiktionary entry “spectrum”, CC BY-SA 4.0. Details