cortex

noun

cor·​tex ˈkȯr-ˌteks 

plural cortices ˈkȯr-tə-ˌsēz  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

Since Kristen’s brain is so scrambled there is a game of telephone between her ear drums and her frontal cortex, this is probably the director that everyone has been speculating Michelle is messing around with but Kristen interpreted it as an actor. —Brian Moylan, Vulture, 7 May 2024

Watching the hand of someone of the same race being poked with a needle activates the anterior cingulate cortex, a region implicated in feelings of empathy; being shown the same with the hand of a person of another race produces less activation. —Robert Sapolsky, Foreign Affairs, 12 Feb. 2019

Yet scientists have discovered animals possess structural equivalents to the human cortex, remarkable for its specialized neurons and patterns of connectivity that reveal the functions of both creating and responding to communication. —T. Nelson Thompson, Baltimore Sun, 14 June 2024

In June 2021, a cancerous tumor was found in her adrenal cortex, the reason for her lingering left-side pain. —Jessica Van Egeren, Journal Sentinel, 13 June 2024

Word History

Etymology

Latin cortic-, cortex bark — more at cuirass

First Known Use

circa 1676, in the meaning defined at sense 1a(1)

Phrases Containing cortex

• cerebral cortex
• piriform cortex
• prefrontal cortex
• pyriform cortex
• visual cortex

Kids Definition

cortex

noun

cor·​tex ˈkȯr-ˌteks 

plural cortices ˈkȯrt-ə-ˌsēz  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

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