cortex

American  

[kawr-teks] / ˈkɔr tɛks /

noun

cortices 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

• cortically
  adverb
• subcortex
  noun
• cortical
  adjective

Inflected Forms

noun

• 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

A study in the Journal of Cognitive Neuroscience showed participants’ brains could automate tasks by offloading them from the prefrontal cortex to the temporal cortex.

From The Wall Street Journal • Jun. 12, 2026

The scientists found that, while first learning the task, the participants’ prefrontal cortex was activated.

From The Wall Street Journal • Jun. 12, 2026

For him, there's a strong neurological factor – young men's attitude to sports, money, and prediction markets is down to what he describes as "an underdeveloped pre-frontal cortex and a high appetite for risk".

From BBC • May 21, 2026

Two key regions are often involved: the amygdala, which helps shape the sense of safety or threat, and the prefrontal cortex, which supports planning, decision making, and emotional control.

From Science Daily • May 16, 2026

In the cortex, you feel your emotions and you make sense of what your senses are telling you.

From "Phineas Gage" by John Fleischman