Definition of medulla in English:



  • 1The 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 adrenaline’
    • ‘Each strand of hair is constructed of three components - the cuticle, cortex and medulla.’
    • ‘Melanin pigment, associated with melanocytes, is more typically leptomeningeal based, particularly in the ventral medulla and cervical spinal cord regions.’
    • ‘The biopsy specimen consisted of renal cortex and outer medulla and contained 17 glomeruli.’
    • ‘The adrenal cortex is of mesodermal origin, whereas the adrenal medulla is derived from the neural crest.’
    • ‘The nodules did not invade the adrenal capsule or adrenal medulla.’
    1. 1.1
      • ‘The cerebrum, pons, and medulla were hypoplastic.’
      • ‘Similar changes may be seen in the medulla and upper brain stem.’
      • ‘The medulla, or brain stem, controls or influences all of the bodily functions that you do not have to think about, like breathing, heart rate, temperature and consciousness.’
      • ‘The brainstem consists of the midbrain, pons and medulla, structures located deep in the back of the brain.’
      • ‘Removal of the meninges and some cranial nerve roots allow salient features of the ventral or anterior aspect of the medulla and pons to be examined more easily.’
    2. 1.2Botany mass noun The soft internal tissue or pith of a plant.
      ‘the main bulk of the potato tuber is pith or medulla’
      • ‘Chloroplasts were abundant in the secondary cortex and secondary phloem, and occurred throughout the secondary xylem rays and medulla of 3-year-old stems.’


Late Middle English (in the sense ‘bone marrow’): from Latin, ‘pith or marrow’.