medulla

 
Pronunciation: /mɛˈdʌlə/

noun

Anatomy
  • the inner region of an organ or tissue, especially when it is distinct from the outer region or cortex (as in a kidney, an adrenal gland, or hair): the adrenal medulla produces adrenalin
  • short for medulla oblongata.
  • [mass noun] Botany the soft internal tissue or pith of a plant: the main bulk of the potato tuber is pith or medulla

Derivatives

medullary

adjective

Origin:

late Middle English (in the sense 'bone marrow'): from Latin, 'pith or marrow'