platelet

American  

[pleyt-lit] / ˈpleɪt lɪt /

noun

Cell Biology.

1. a small platelike body, especially a blood platelet.

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platelet British  

/ ˈpleɪtlɪt /

noun

1. Formerly called: thrombocyte.  a minute cell occurring in the blood of vertebrates and involved in clotting of the blood

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platelet Scientific  

/ plāt′lĭt /

1. Any of the numerous small, round cell fragments found in the blood of mammals that function in the clotting of blood. Platelets contain no nuclei and are formed in the bone marrow from precursor cells called megakaryocytes. Platelets contribute to the coagulation process by adhering to damaged blood vessels, fibrinogen, and other platelets. An inadequate number of platelets leads to uncontrolled bleeding.

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Etymology

Origin of platelet

First recorded in 1890–95; plate ¹ + -let

Explanation

Platelets are tiny cell fragments that help your blood to clot. If you cut yourself, platelets clump together to slow the flow of blood and plug the cut. Blood clots are your body's way of repairing and healing cuts and scrapes in your skin, and platelets are an essential part of the clotting process. They're colorless disks, pieces of cells with no nuclei, and they're formed in your bone marrow along with white and red blood cells. Doctors and scientists measure blood in microliters, tiny drops, and a healthy person has as many as 450,000 platelets in one microliter of blood.

Example Sentences

Since her diagnosis, Sian has been undergoing treatment to shrink her enlarged spleen and receiving weekly blood and platelet transfusions.

From BBC • Jan. 26, 2026

With age, immune cells produce less platelet factor 4.

From Science Daily • Dec. 31, 2025

Writing in the journal Blood, the researchers report that aging is linked to declining levels of a protein called platelet factor 4.

From Science Daily • Dec. 31, 2025

Ms Claxton regularly needed blood and platelet transfusions and ended up in the intensive care ward four times.

From BBC • Dec. 20, 2025

Bull had started down the slope now, his boards out, and he was descending, alive, alive, adrenaline reinforcing every platelet, every blood cell, and his mind radiating with its response to danger.

From "The Great Santini" by Pat Conroy