gray matter

noun

1
: neural tissue especially of the brain and spinal cord that contains nerve-cell bodies as well as nerve fibers and has a brownish-gray color
2
: brains, intellect
The key to his surge has been an increased use of his gray matterAustin Murphy

Examples of gray matter in a Sentence

she's got the gray matter to figure that equation out
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
In the brain, MRI can differentiate between white matter and gray matter and can also be used to diagnose aneurysms and tumors. Jenna Prestininzi, Freep.com, 28 Oct. 2025 The researchers looked specifically at where gray matter (the body of a neuron) intersects with white matter (the long axons that project out of the cell body) — an area thought to be particularly vulnerable to head impacts. The New York Times News Service Syndicate, San Diego Union-Tribune, 14 Oct. 2025 Those with less social connection were also found to have smaller gray matter volume in regions of the brain associated with thinking and learning. Arianna Huffington, Time, 1 Oct. 2025 Some studies reported smaller gray matter volumes in children with ADHD compared to those without, while others showed no difference or even larger volumes. New Atlas, 8 Sep. 2025 See All Example Sentences for gray matter

Word History

First Known Use

1809, in the meaning defined at sense 1

Time Traveler
The first known use of gray matter was in 1809

Browse Nearby Words

Cite this Entry

“Gray matter.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/gray%20matter. Accessed 9 Nov. 2025.

Kids Definition

gray matter

noun
1
: nerve tissue especially of the brain and spinal cord that has a brownish gray color
2

Medical Definition

gray matter

noun
: neural tissue especially of the brain and spinal cord that contains cell bodies as well as nerve fibers, has a brownish gray color, and forms most of the cortex and nuclei of the brain, the columns of the spinal cord, and the bodies of ganglia

called also gray substance

More from Merriam-Webster on gray matter

Last Updated: - Definition revised
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!