Webster’s Revised Unabridged Dictionary · 1913
Cortex
Cor′tex (k?r′t?ks), n.; pl. Cortices (-tĭ-sēz). [L., bark. Cf. Cork.] 1. Bark, as of a tree; hence, an outer covering.
2. (Med.) Bark; rind; specifically, cinchona bark.
3. (Anat.) The outer or superficial part of an organ; as, the cortex or gray exterior substance of the brain.