cortex

UK: /ˈkɔː^rtɛks/ US: /ˈkɔrtɛks/ ,(kôr′teks)

Inflections of 'cortex' (n): npl: cortices

WordReference Random House Learner's Dictionary of American English © 2026

cor•tex /ˈkɔrtɛks/   n. [countable] , pl. -ti•ces 

/-təˌsiz/.  
1. Anatomy, Zoology the outer layer of a body organ or structure, as of the cerebrum.
2. Botany the bark of a plant stem or tree trunk.

WordReference Random House Unabridged Dictionary of American English © 2026

cor•tex  (kôr′teks), n., pl. -ti•ces 

(-tə sēz′). 
1. Anatomy, Zoology
   • the outer region of an organ or structure, as the outer portion of the kidney.
   • the cerebral cortex.
2. [Bot.]
   • Botany the portion of a stem between the epidermis and the vascular tissue;
     bark.
   • Botany any outer layer, as rind.
3. Fungi [Mycol.] the surface tissue layer of a fungus or lichen, composed of massed hyphal cells.

• Latin: bark, rind, shell, husk
• 1650–60

Collins Concise English Dictionary © HarperCollins Publishers::

cortex / ˈkɔːtɛks/ noun ( -tices / -tɪˌsiːz/)

1. 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. the unspecialized tissue in plant stems and roots between the vascular bundles and the epidermis
3. the outer layer of a part such as the bark of a stem

Etymology: 17th Century: from Latin: bark, outer layer

cortical / ˈkɔːtɪk^əl/ adjective