Definition of: cortex

(kôr′teks) noun plural ·ti·ces (-tə·sēz)
1. Bot. The outer portion of the stem, thalli, or root in plants; specifically, the bark of trees or the rind of fruits.
2. Zool. In animals, the outer or investing layer of various organs.
3. Anat. a The external layer of gray matter of the cerebrum and cerebellum. b The external portion of the adrenal glands, enclosing the medullae and indispensable to proper glandular functioning. [<L, bark]