rhizoverbBeta
DictionarymarrowTissue inside bones
noun

marrow

MAIR-oh/ˈmærəʊ/

The soft tissue enclosed inside bones.

Red marrow inside the pelvic bone produces new blood cells.

An anatomically credible cutaway of an adult human pelvic bone exposes red marrow within spongy bone, with one small circular magnified detail showing developing blood cells beside a marrow sinusoid.
Etymology
marrowOld Englishmarrow

Old English mearg already named the substance inside bones, so the anatomical meaning is inherited. Its interior location also underlies the figurative use of marrow for the innermost substance or essence of something.

In context

Whaling Museum2:20
unlike ivory bone has marrow at its core from which a series of tiny blood vessels extend out into the bone
Lecture: Caring for Bone and Ivory Objects

More examples

  • Doctors collect a small sample of bone marrow for testing.
  • The roasted bones contain rich, creamy marrow.
  • Yellow marrow stores fat inside certain bones.