cortex
/ˈkɔ:teks; `kɔrtɛks/ n
(pl cortices / ˈkɔ:tɪsi:z;`kɔrtɪˌsiz/)
1 (medical 医) outer layer of the brain or other organ （脑或其他器官的）皮层, 皮
the cerebral cortex 大脑皮层
the renal cortex, ie the outer layer of the kidney 肾皮层（肾的表层）.
2 outer layer of a plant, eg the bark of a tree 植物的表层（如树皮）.