Cortex

Cortex is a word that comes from Latin language, and that is usually translated as shell or bark. The term is used for different concepts: 
Cortex (botany), the outer layer of a stem or bark.
Cortex (archaeology), the outer layer of rock
Cell cortex, directly below the cell membrane
Cortex (anatomy), the outermost layer of an organ
Renal cortex, the outermost layer of the kidney
Adrenal cortex, the outermost layer of the adrenal gland
Cerebral cortex, a region of the brain