marrow
n. uncountablen. the soft, spongy tissue inside your bones that makes blood cells. You use this word when talking about health or anatomy.
n. the soft, vascular tissue found within the cavities of bones, responsible for the production of blood cells.
The doctor checked the marrow for signs of disease.
The surgeon carefully extracted a sample of bone marrow to test for leukemia.
In severe cases of radiation sickness, the bone marrow is damaged, requiring a transplant to restore the body's ability to produce healthy blood cells.
From Middle English mary, marow, marwe, marowȝ, from Old English mearg, from Proto-West Germanic maʀg, from Proto-Germanic mazgą, mazgaz, from Proto-Indo-European mosgʰos. Compare West Frisian moarch, Dutch merg, German Mark, Swedish märg, Icelandic mergur, and also Russian мозг (mozg, “brain”), Polish mózg (“brain”), Ashkun amōźã, Kamkata-viri muč, muj, Waigali muj, Persian مغز (maġz, “brain”), Sanskrit मज्जन् (majján). Doublet of maghaz.
From Old Norse margr.