white matter

American  

noun

Anatomy.

1. nerve tissue, especially of the brain and spinal cord, which primarily contains myelinated fibers and is nearly white in color.

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white matter British  

noun

1. Technical name: substantia alba.  the whitish tissue of the brain and spinal cord, consisting mainly of myelinated nerve fibres Compare grey matter

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white matter Scientific  

1. The whitish tissue of the vertebrate brain and spinal cord, made up chiefly of nerve fibers (axons) covered in myelin sheaths.

2. Compare gray matter

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Etymology

Origin of white matter

First recorded in 1830–40

Compare meaning

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

• gray matter vs. white matter

Example Sentences

In this new study, researchers noticed that participants scanned within 16 months of infection showed higher levels of inflammatory activity in white matter than those who had been sick for a longer period.

From Science Daily • May 28, 2026

Importantly, the increased risk was not explained by overall brain shrinkage or damage to white matter.

From Science Daily • Jan. 15, 2026

The scans helped show white matter, the fatty substance that insulates the nerve fibers connecting brain regions.

From The Wall Street Journal • Dec. 23, 2025

The second epoch, adolescence, is marked by continued growth of white matter.

From Science Daily • Dec. 1, 2025

The mystery would remain complete; no doctor has been able to discover or could discover the psyche in those round or fusiform cells, in the white matter or grey substance of the brain.

From En Route by Huysmans, J.-K. (Joris-Karl)