cortex
Americannoun
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cortices,
plural
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cortexes
plural
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Anatomy, Zoology.
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the outer region of an organ or structure, as the outer portion of the kidney.
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the cerebral cortex.
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Botany.
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the portion of a stem between the epidermis and the vascular tissue; bark.
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any outer layer, as rind.
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Mycology. the surface tissue layer of a fungus or lichen, composed of massed hyphal cells.
noun
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anatomy the outer layer of any organ or part, such as the grey matter in the brain that covers the cerebrum ( cerebral cortex ) or the outer part of the kidney ( renal cortex )
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botany
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the unspecialized tissue in plant stems and roots between the vascular bundles and the epidermis
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the outer layer of a part such as the bark of a stem
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The outer layer of an organ or body part, such as the cerebrum or the adrenal glands.
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The region of tissue lying between the epidermis (the outermost layer) and the vascular tissue in the roots and stems of plants. It is composed of collenchyma, parenchyma, and sclerenchyma. In roots the cortex transfers water and minerals from the epidermis to the vascular tissue, which distributes them to other parts of the plant. The cortex also provides structural support and stores food manufactured in the leaves.
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See illustration at xylem
Other Word Forms
Derived Forms
Inflected Forms
Nouns
Etymology
Origin of cortex
1650–60; < Latin: bark, rind, shell, husk
Explanation
The cortex refers to the outer layer of an organ or structure in the body, like the brain, where it plays a crucial role in processing information and thoughts. The cortex in any organ helps to protect it and make sure it functions properly. For example, the brain's cerebral cortex is crucial for high-level functions like memory, attention, thought, and consciousness. However, the term isn't exclusive to the brain; the kidney and adrenal glands also have a cortex essential to their operation. In each case, the cortex plays an important role in maintaining the organ’s overall health.
Vocabulary lists containing cortex
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
Adolescents already have a harder time than adults with planning ahead and controlling their impulses, because of the brain’s immature prefrontal cortex.
From The Wall Street Journal ● Oct. 3, 2026
Psychiatric disorders were associated with elevated PAD in the frontal and temporal lobes, while dementia was linked to higher PAD in the frontal and occipital cortex.
From Science Daily ● Sep. 29, 2026
One area that stood out was the prefrontal cortex, which showed higher PAD across multiple brain disorders.
From Science Daily ● Sep. 29, 2026
Radial glia are also believed to contribute to the unusually large expansion of the human cortex compared with that of other species.
From Science Daily ● Sep. 4, 2026
The visual cortex in your brain is activated when your auditory cortex is stimulated.”
From "A Mango-Shaped Space" by Wendy Mass
"Both the frontal and posterior temporal cortexes disrupt semantic integration, which we see happen in individuals with various aphasias," Murphy said.
From Science Daily ● Oct. 24, 2023
I think the thing now is the way we are stressed by putting these excessive demands on our very powerful prefrontal cortexes, which I think is more of what makes us human than language.
From Salon ● Dec. 13, 2021
A select number of Americans, it should be noted, don’t even own a flat-screen, tablet or other instrument of destruction delivering all this rottery into our cerebral cortexes.
From Seattle Times ● Aug. 29, 2021
McKee and other experts said one or two tangles can be found in the cortexes of otherwise healthy 50-year-olds.
From Washington Post ● Jan. 22, 2020
“In fact, it is one of the largest lateral prefrontal cortexes I’ve ever seen. Yet the orbitofrontal cortex is remarkably small. What do these two facts indicate?”
From "Insurgent" by Veronica Roth
Research has shown that the premotor and posterior parietal cortices, along with the temporoparietal junction, are active in the brain when we are locating or thinking about ourselves.
From Salon ● May 26, 2025
The analyses unveiled a nuanced architecture of mixed feedback and feedforward processing, spanning frontal and temporal cortices.
From Science Daily ● Oct. 11, 2023
The workspace is a network of cortical neurons in the front of the brain, with long-range projections to similar neurons distributed all over the neocortex in prefrontal, parietotemporal and cingulate associative cortices.
From Scientific American ● Sep. 8, 2023
In one 2022 study, Fani, Harnett and their colleagues reported that among 81 Black women who had experienced trauma, those who reported experiencing more racial discrimination showed proportionally thinner gray matter in the cingulate cortices.
From Washington Post ● Feb. 16, 2023
If such a thing as telepathy existed, one of its glories would be the opportunity for each of us to read the books in the cerebral cortices of our loved ones.
From "Cosmos" by Carl Sagan
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
