spectrum

1. (psychology, education, usually with the) The autism spectrum.Examples: "He punctuated his words with a look into my eyes that might have been read as threatening or menacing by anyone who was not on the spectrum. But I am on the spectrum, and so I stared back at him."usually

2. (chemistry) The pattern of absorption or emission of radiation produced by a substance when subjected to energy (radiation, heat, electricity, etc.).

3. (mathematics, linear algebra) The set of eigenvalues of a matrix.Synonyms: eigenspectrum

4. (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.

5. (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

6. (obsolete) Specter, apparition.obsolete