cor·​tex | \ ˈkȯr-ˌteks How to pronounce cortex (audio) \
plural cortices\ ˈkȯr-​tə-​ˌsēz How to pronounce cortices (audio) \ or cortexes

Definition of cortex

1a(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
3a : 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 The olfactory cortex is also connected to the hippocampus, a warped wishbone lookalike, which is responsible for our learning habits and emotions. Liana Satenstein, Vogue, "How Clinique Happy Engineered My Happiness," 31 Oct. 2019 The implants let the man — only identified by his first name, Thibault — operate the suit by reading the signals in his sensorimotor cortex, the area of the brain that controls movement. Jason Duaine Hahn,, "28-Year-Old Man Paralyzed from Spine Injury Walks Again Using Brain-Controlled Exoskeleton," 7 Oct. 2019 After nine days of development, mice embryos begin to form a cortex, the outer wrinkly layer of the brain associated with the most sophisticated mental talents. Quanta Magazine, "How Humans Evolved Supersize Brains," 10 Nov. 2015 Past research shows that if someone learns a motor skill during the day, the motor cortex, the region of the brain associated with executing movement, is active at night during certain stages of sleep. Lisa Ward, WSJ, "The Secret to Retaining a New Skill: Learn, Exercise, Sleep," 16 Sep. 2018 The information that reaches the visual cortex is constrained by anatomy: Relatively few nerves connect the visual cortex with the outside world, which limits the amount of visual data the cortex has to work with. Quanta Magazine, "Computers and Humans ‘See’ Differently. Does It Matter?," 17 Sep. 2019 Hundreds of these cortex organoids grew in cultures for 10 months. David Grossman, Popular Mechanics, "Scientists Re-create Baby Brain Readings in a Dish," 19 Nov. 2018 Meyer says social media often negatively affects the frontal cortex, the part of the brain that controls decision-making and isn't fully developed until early adulthood. Dallas News, "When popularity on social media exploded, North Texas teen had to rethink his priorities," 29 July 2019 Instead, there’s talk of brain regions like the cortex. Sigal Samuel, Vox, "How your brain invents morality," 8 July 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'cortex.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of cortex

1677, in the meaning defined at sense 1a(1)

History and Etymology for cortex

Latin cortic-, cortex bark — more at cuirass

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Statistics for cortex

Last Updated

15 Nov 2019

Time Traveler for cortex

The first known use of cortex was in 1677

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How to pronounce cortex (audio)

English Language Learners Definition of cortex

medical : the outer layer of an organ in the body and especially of the brain


cor·​tex | \ ˈkȯr-ˌteks How to pronounce cortex (audio) \
plural cortices\ ˈkȯrt-​ə-​ˌsēz How to pronounce cortices (audio) \ or cortexes

Medical Definition of cortex

1a : 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)
2a : 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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More from Merriam-Webster on cortex

Rhyming Dictionary: Words that rhyme with cortex

Spanish Central: Translation of cortex

Nglish: Translation of cortex for Spanish Speakers

Britannica English: Translation of cortex for Arabic Speakers Encyclopedia article about cortex

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