What does "spectrum" mean?

1. (a range of ideas or things) a wide range of different opinions, people, or ideas that are related to each other. 2. (light and colours) the set of colours you see when light passes through a prism, like a rainbow. 3. (neurodiversity) a way of describing a range of conditions, especially autism, that affect how people think and behave. 4. (mathematical eigenvalues) a special set of numbers related to a square grid of numbers called a matrix. 5. (a ghost) an old word for a ghost or a strange vision.

spectrum

US //ˈspɛktɹəm// UK //spˈɛktɹəm// spec·trum

1 a range of ideas or things (n.)
B2 Upper Intermediate

a wide range of different opinions, people, or ideas that are related to each other.

a broad range of varied but related ideas or objects, often positioned between two opposite points.

Example

The political spectrum includes many different views from the left to the right.

Example

The survey captured a broad spectrum of public opinion, ranging from enthusiastic support to deep-seated skepticism regarding the new policy.
2 light and colours (n.)
B2 Upper Intermediate Science

the set of colours you see when light passes through a prism, like a rainbow.

the distribution of colors produced when light is dispersed by a prism or similar device.

Example

A prism breaks white light into the visible spectrum of colours.

Example

Astronomers analyze the star's light spectrum to determine its chemical composition and temperature.
- rainbow

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3 neurodiversity (n.)
B2 Upper Intermediate Psychology

a way of describing a range of conditions, especially autism, that affect how people think and behave.

a range of conditions or symptoms, specifically used to describe the variety of ways autism manifests in individuals.

Example

Because autism is a spectrum, every person has different strengths and challenges.

Example

Clinicians now recognize that these behaviors exist on a spectrum rather than being distinct, unrelated disorders.
4 mathematical eigenvalues (n.)
C2 Proficiency Technical Math

a special set of numbers related to a square grid of numbers called a matrix.

the set of eigenvalues of a matrix or, more generally, of a bounded linear operator.

Example

The professor asked us to calculate the spectrum of the given matrix.

Example

In functional analysis, the spectrum of an operator generalizes the concept of eigenvalues for finite-dimensional matrices.
5 a ghost (n.)
C2 Proficiency Archaic Literary

an old word for a ghost or a strange vision.

a phantom, ghost, or apparition; the Latin root of the modern word.

Example

The old story spoke of a spectrum that haunted the castle halls.

Example

The poet described a pale spectrum rising from the mist, a lingering shadow of a forgotten era.

Origin

From Latin spectrum (“appearance, image, apparition”), from speciō (“look at, view”). Doublet of specter. See also scope.