gray matter

American  

noun

1. Anatomy. nerve tissue, especially of the brain and spinal cord, that contains fibers and nerve cell bodies and is dark reddish-gray.

2. Informal. brains or intellect.

---

gray matter Scientific  

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

2. Compare white matter

---

gray matter Idioms  

1. 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]

---

Etymology

Origin of gray matter

First recorded in 1830–40

Compare meaning

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

• gray matter vs. white matter

Example Sentences

See Examples For:

gray matter

"Our findings suggest that cognitive health depends not only on how much gray matter is preserved, but also on the condition of the wiring that connects it."

From Science Daily ● Sep. 14, 2026

Measures of gray matter atrophy were still the strongest overall predictors of cognitive ability.

From Science Daily ● Sep. 14, 2026

Using the MRI scans, they measured the volume of gray matter and white matter in each participant's brain while accounting for differences in overall brain size.

From Science Daily ● Jul. 1, 2026

Its inner region, called gray matter, contains nerve cell bodies along with astrocytes.

From Science Daily ● Feb. 13, 2026

“Our gray matter is still, like, ten percent mashed potatoes.”

From "A Place at the Table" by Saadia Faruqi and Laura Shovan