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gray matter

noun

Anatomy. nerve tissue, especially of the brain and spinal cord, that contains fibers and nerve cell bodies and is dark reddish-gray. Compare white matter.
Informal. brains or intellect.

gray matter

The brownish-gray tissue of the vertebrate brain and spinal cord, made up chiefly of the cell bodies and dendrites of neurons.
Compare white matter

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Word History and Origins

Origin of gray matter¹

First recorded in 1830–40

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Idioms and Phrases

Brains, intellect, as in If you'd only use your gray matter, you'd see the answer in a minute . This expression refers to actual brain tissue that is gray in color. Agatha Christie's fictional detective, Hercule Poirot, constantly alludes to using the little gray cells for solving a crime. [Late 1800s]

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Compare Meanings

How does gray matter compare to similar and commonly confused words? Explore the most common comparisons:

gray matter vs. white matter

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

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