marrow

¹ American  

[mar-oh] / ˈmær oʊ /

noun

1. Anatomy. a soft, fatty, vascular tissue in the interior cavities of bones that is a major site of blood cell production.

2. the inmost or essential part.

   to pierce to the marrow of a problem.

3. strength or vitality.

   Fear took the marrow out of him.

4. rich and nutritious food.

5. Chiefly British. vegetable marrow.

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marrow ² American  

[mar-oh, mar-uh] / ˈmær oʊ, ˈmær ə /

noun

Scot. and North England.

1. a partner; fellow worker.

2. a spouse; helpmate.

3. a companion; close friend.

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marrow ¹ British  

/ ˈmærəʊ, -rə /

noun

1. dialect a companion, esp a workmate

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marrow ² British  

/ ˈmærəʊ /

noun

1. the fatty network of connective tissue that fills the cavities of bones

2. the vital part; essence

3. vitality

4. rich food

5. short for vegetable marrow

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marrow Scientific  

/ măr′ō /

1. See bone marrow

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marrow Cultural  

1. The soft, specialized connective tissue that fills the cavities of bones. One kind of bone marrow is responsible for manufacturing red blood cells in the body.

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Other Word Forms

• marrowish adjective
• marrowless adjective
• marrowy adjective

Etymology

Origin of marrow¹

First recorded before 900; Middle English marw(e), marwa, Old English mearg, merg; cognate with Dutch merg, German Mark, Old Norse mergr

Origin of marrow²

First recorded in 1400–50; late Middle English marwe, maro(we), “fellow worker, partner,” perhaps from Old Norse margr “many; friendly”

Example Sentences

It starts in the bone marrow and attacks the body on several fronts.

From Slate • Mar. 29, 2026

The health board said the proposal was "necessary" after ongoing defects disrupted the running of the adult bone marrow transplant unit.

From BBC • Mar. 23, 2026

The treatment, known as anito-cel, is designed for patients with multiple myeloma, a blood cancer arising from plasma cells in the bone marrow.

From Barron's • Feb. 23, 2026

Birria gyoza arrived swimming in bone marrow consommé, delivering a concentrated hit of richness.

From Salon • Feb. 2, 2026

“The marrow of his bone ...” I repeated aimlessly.

From "A Separate Peace" by John Knowles