cortex
noun
cor·tex
ˈkȯr-ˌteks 
plural cortices
ˈkȯr-tə-ˌsēz
also cortexes
also cortexes
1
a(1)
: the outer or superficial part of an organ or bodily structure (such as the kidney, adrenal gland, or cerebellum or a bone)
especially
: cerebral cortex
(2)
: the proteinaceous usually pigmented layer of a hair below the cuticle
b
: the outer part of some organisms (such as paramecia)
2
: a plant bark or rind (such as cinchona) used medicinally
3
a
: the typically parenchymatous layer of tissue external to the vascular tissue and internal to the corky or epidermal tissues of a green plant
broadly
: all tissues external to the xylem
b
: an outer or investing layer of various algae, lichens, or fungi
Examples of cortex in a Sentence
Recent Examples on the Web
Her brain imaging work shows that the same areas of the motor cortex help control muscles used in both speech and dance.
—
David L. Coddon, San Diego Union-Tribune, 22 May 2025
When she was asked to imagine visiting the rooms of her house, blood flowed to different parts of her brain, including the parahippocampal gyrus, a strip of cortex crucial for spatial navigation.
—Sarah Zhang, The Atlantic, 16 May 2025
The cells in the embryo’s cortex region end up in the adult cortex.
—Yasemin Saplakoglu, Wired News, 11 May 2025
The researchers knew that spatial navigation and episodic memories are encoded in the temporal lobe, specifically in the medial entorhinal cortex (MEC).
—Avery Hurt, Discover Magazine, 2 May 2025
See All Example Sentences for cortex
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David L. Coddon, San Diego Union-Tribune, 22 May 2025
When she was asked to imagine visiting the rooms of her house, blood flowed to different parts of her brain, including the parahippocampal gyrus, a strip of cortex crucial for spatial navigation.
—Sarah Zhang, The Atlantic, 16 May 2025
The cells in the embryo’s cortex region end up in the adult cortex.
—Yasemin Saplakoglu, Wired News, 11 May 2025
The researchers knew that spatial navigation and episodic memories are encoded in the temporal lobe, specifically in the medial entorhinal cortex (MEC).
—Avery Hurt, Discover Magazine, 2 May 2025
See All Example Sentences for cortex
Cite this Entry
“Cortex.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/cortex. Accessed 1 Jun. 2025.
Copy CitationKids Definition
cortex
noun
cor·tex
ˈkȯr-ˌteks
plural cortices
ˈkȯrt-ə-ˌsēz
or cortexes
or cortexes
1
: an outer or surrounding layer of an organ or body part
the cortex of the kidney
especially
: the outer layer of gray matter of the cerebrum
2
: the layer of tissue outside the xylem and phloem and inside the corky or epidermal tissues of a vascular plant
also
: all tissues external to the xylem
Medical Definition
cortex
noun
cor·tex
ˈkȯr-ˌteks
plural cortices
ˈkȯrt-ə-ˌsēz
also cortexes
also cortexes
1
a
: the outer or superficial part of an organ or body structure (as the kidney, adrenal gland, or a hair)
especially
: cerebral cortex
b
: the outer part of some organisms (as paramecia)
2
a
: a plant bark or rind (as cinchona) used medicinally
b
: the peel of any of several fruits
—used especially in the writing of medical prescriptions
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