noun
greyish nervous tissue containing cell bodies as well as fibers; forms the cerebral cortex consisting of unmyelinated neurons
• Syn: ↑grey matter, ↑grey substance, ↑gray substance, ↑substantia grisea
• Hypernyms: ↑nervous tissue, ↑nerve tissue
• Substance Holonyms: ↑cerebral cortex, ↑cerebral mantle, ↑pallium, ↑cortex
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noun [noncount]
: the tissue that makes up the brain
— often used figuratively to refer to a person's intelligence
His books are enjoyable, but they don't do much to challenge the reader's gray matter. [=intelligence]
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a person's intelligence
•
This should exercise the old grey matter.
Useful english dictionary. 2012.