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

Try the bone marrow butter or crabmeat bearnaise for a real upscale treat. —Tara Massouleh McCay, Southern Living, 6 Sep. 2024

Leukemia affects blood-forming organs, including the bone marrow, thymus, spleen, and lymph nodes. —Carrie Madormo, Rn, Health, 8 Aug. 2024

When Jefferson was 17 years old, her dad was diagnosed with myelodysplastic syndrome, a disorder in which the bone marrow doesn’t create enough new blood cells; the condition can lead to leukemia (blood cancer) if left untreated. —Erica Sloan, SELF, 8 Aug. 2024

In most cases, leukemia starts in the bone marrow and then spreads through the bloodstream. —Carrie Madormo, Rn, Health, 8 Aug. 2024

Word History

First Known Use

1590, in the meaning defined above

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