cortex
Americannoun
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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:
The same categorization task was now being handled mainly by the temporal cortex, a region involved in memory and recognizing complex objects.
From Science Daily ● Jul. 12, 2026
At the same time, your brain’s amygdala, or fear and emotion center, calms down and its prefrontal cortex, which governs rational thought, amps up.
From The Wall Street Journal ● Jun. 27, 2026
When activity in either the auditory cortex or somatosensory cortex was disrupted, participants showed significantly poorer retention of the speech movements they had learned.
From Science Daily ● Jun. 23, 2026
Although double-strand breaks are typically associated with mutations, cell dysfunction, and even cell death, the researchers discovered that they are a normal part of brain cortex development.
From Science Daily ● Jun. 21, 2026
The cerebral cortex, where matter is transformed into consciousness, is the point of embarkation for all our cosmic voyages.
From "Cosmos" by Carl Sagan
"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
Prefrontal cortexes, responsible for impulse control, don’t finish developing until the mid-20s.
From Washington Post ● May 27, 2022
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
Though no writer can avoid idioms altogether—they’re part of the English lexicon, just like individual words—good writers reach for fresh similes and metaphors that keep the reader’s sensory cortexes lit up.
From "The Sense of Style" by Steven Pinker
Extensive preclinical work in the motor and visual cortices was carried out with Dr. Tolias and Bijan Pesaran, professor of neurosurgery at the University of Pennsylvania, both recognized leaders in computational and systems neuroscience.
From Science Daily ● Dec. 9, 2025
In fact, neuroimaging studies show the brains of children who eat more processed snack foods are smaller in volume, particularly in the frontal cortices, than those of children who eat a more healthful diet.
From Salon ● May 28, 2024
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
According to neuroscientists, what makes a creative thinker is the high activity in the association cortices sections of the brain—responsible for making new connections and for “eureka” moments.
From "Music and the Child" by Natalie Sarrazin
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.
