bone marrow

noun

: a soft highly vascular modified connective tissue that occupies the cavities of most bones and occurs in two forms:

a

: one that is yellowish, consists chiefly of fat cells, and is found especially in the cavities of long bones

b

: one that is reddish, is the chief site of blood cell formation, and occurs in the normal adult in cancellous tissue especially of certain flat bones

called also red marrow

Examples of bone marrow in a Sentence

Recent Examples on the Web

Prolonged exposure can weaken the immune system, damage bone marrow, leading to conditions like anemia, and cause neurological effects such as dizziness, headaches, and long-term nerve damage. —Josh Hammer, Newsweek, 19 Mar. 2025

Conventionally it was thought that hematopoietic stem cells (HSCs) which produce different types of blood cells were mostly found in the bone marrow, a spongy mass found in the middle of large bones like the legs and hips. —Victoria Forster, Forbes, 15 Mar. 2025

Multiple myeloma, often referred to simply as myeloma, is a complex and frequently misunderstood blood cancer that originates in the bone marrow and affects the immune system. —Oumou Fofana, Essence, 27 Feb. 2025

These days, early treatment with bone marrow from a parent or sibling can save most SCID patients. —Scott Lafee, San Diego Union-Tribune, 4 Feb. 2025

Word History

First Known Use

1590, in the meaning defined above

Rhymes for bone marrow

• caballero
• mescalero
• aero
• faro
• garo
• narrow
• pharaoh
• sparrow
• taro
• bolero
• bracero
• estero

Kids Definition

bone marrow

noun

: a soft tissue rich in blood vessels that fills the cavities of most bones and occurs in two forms:

a

: one that is yellowish and fatty and is found especially in long bones (as the femur)

b

: one that is reddish, is the main place where blood cells are formed, and in adults is limited especially to certain flat or short bones (as the ribs)

Medical Definition

bone marrow

noun

: a soft highly vascular modified connective tissue that occupies the cavities and cancellous part of most bones and occurs in two forms:

a

: a whitish or yellowish bone marrow that consists chiefly of fat cells and is found especially in the cavities of the long bones

called also yellow marrow

b

: a reddish bone marrow that contains little fat, is the chief site of red blood cell and blood granulocyte formation, and occurs in the normal adult in cancellous tissue especially of certain flat bones

called also red marrow