Noun

(en-noun)

An outline or image universally applicable to a general conception, under which it is likely to be presented to the mind (for example, a ).

(databases) A formal description of the structure of a database: the names of the tables, the names of the columns of each table, and the data type and other attributes of each column.

(markup languages) A formal description of data, data types, and data file structures, such as for XML files.

(logic) A formula in the language of an axiomatic system, in which one or more schematic variables appear, which stand for any term or subformula of the system, which may or may not be required to satisfy certain conditions.

Noun

(en-noun)

Specter, apparition.

A range; a continuous, infinite, one-dimensional set, possibly bounded by extremes.

* {{quote-news, year=2012, date=November 7, author=Matt Bai, title=Winning a Second Term, Obama Will Confront Familiar Headwinds, work=New York Times citation

, passage=As Mr. Obama prepared to take the oath, his approval rating touched a remarkable 70 percent in some polling — a reflection of good will across the political spectrum .}}

Specifically, a range of colours representing light (electromagnetic radiation) of contiguous frequencies; hence electromagnetic spectrum, visible spectrum, ultraviolet spectrum, etc.

* 2010 October 30, Jim Giles, Jammed!'', in '' ,

Current 3G technologies can send roughly 1 bit of data - a one or a zero - per second over each 1 Hz of spectrum that the operator owns.

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

(mathematics, linear algebra) The set of eigenvalues of a matrix.

(mathematics, functional analysis) Of a bounded linear operator A'', the set of scalar values ? such that the operator ''A—?I'', where ''I denotes the identity operator, does not have a bounded inverse; intended as a generalisation of the linear algebra sense.