CORTEX
cortex
(noun) the tissue forming the outer layer of an organ or structure in plant or animal
Source: WordNet® 3.1
Etymology
Noun
cortex (countable and uncountable, plural cortexes or cortices)
(countable, anatomy) The outer layer of an internal organ or body structure, such as the kidney or the brain.
(uncountable, botany) The tissue of a stem or root that lies inward from the epidermis, but exterior to the vascular tissue.
Source: Wiktionary
Cor"tex (kr"tks), n.; pl. Cortices (-t. Etym: [L., bark. Cf. Cork.]
1. Bark, as of a tree; hence, an outer covering.
2. (Med.)
Definition: Bark; rind; specifically, cinchona bark.
3. (Anat.)
Definition: The outer or superficial part of an organ; as, the cortex or
gray exterior substance of the brain.
Source: Webster’s Unabridged Dictionary 1913 Edition