cortex

American  

[kawr-teks] / ˈkɔr tɛks /

noun

• cortices,
  plural
• cortexes
  plural

1. Anatomy, Zoology.

   1. the outer region of an organ or structure, as the outer portion of the kidney.

   2. the cerebral cortex.

2. Botany.

   1. the portion of a stem between the epidermis and the vascular tissue; bark.

   2. any outer layer, as rind.

3. Mycology. the surface tissue layer of a fungus or lichen, composed of massed hyphal cells.

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cortex British  

/ ˈkɔːtɛks, ˈkɔːtɪkəl /

noun

1. 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 )

2. botany

   1. the unspecialized tissue in plant stems and roots between the vascular bundles and the epidermis

   2. the outer layer of a part such as the bark of a stem

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cortex Scientific  

/ kôr′tĕks′ /

1. The outer layer of an organ or body part, such as the cerebrum or the adrenal glands.

2. 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.

3. See illustration at xylem

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Other Word Forms

Derived Forms

• subcortex
  noun
• cortical
  adjective
• cortically
  adverb

Inflected Forms

Nouns

• cortexes
  plural
• cortices
  plural

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.

Example Sentences

See Examples For:

cortex cortexes cortices

The new research extended those findings by examining how adaptable the frontoparietal cortex is.

From Science Daily ● Aug. 20, 2026

Scientists have long recognized the frontoparietal cortex as an important part of decision making.

From Science Daily ● Aug. 20, 2026

In a study published in 2025, Hwang and his colleagues found that the frontoparietal cortex develops an ongoing high-level summary of information arriving from elsewhere in the brain.

From Science Daily ● Aug. 20, 2026

University of Iowa researchers have provided new insight into the brain's information hub, known as the frontoparietal cortex.

From Science Daily ● Aug. 20, 2026

By that point, entire sectors of my cerebral cortex seemed to have shut down altogether.

From "Into Thin Air" by Jon Krakauer

"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

“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

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

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 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