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

Rapidly progressing symptoms include high levels of mast cells in the blood, severe organ dysfunction, and bone marrow failure. —Sarah Jividen, Verywell Health, 11 July 2024

Many of the bones had cut marks that showed the Denisovans were processing the animals for their hides as well as meat and bone marrow. —Katie Hunt, CNN, 3 July 2024

Dengue can rarely have serious effects on the liver, heart, central nervous system, kidneys, eyes, muscles or bone marrow, and severe dengue can lead to death. —Emily Deletter, USA TODAY, 26 June 2024

While a bone marrow biopsy is necessary for diagnosis, biopsies of your skin or other affected organs may also be used. —Anna Giorgi, Verywell Health, 9 July 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