platelet

American  

[playt-lit] / ˈpleɪt lɪt /

noun

Cell Biology.

• platelets
  plural

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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Other Word Forms

Noun Inflected Forms

• platelets
  plural

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Etymology

Origin of platelet

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

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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

See Examples For:

platelet platelets

He spent nine days on a ventilator and 18 days on dialysis, during which time doctors gave him blood, platelet and plasma transfusions.

From Salon ● Jun. 22, 2026

As my blood counts fluctuated, and infections threatened, our middle sibling, Art Landro, provided platelet support collected from his blood.

From The Wall Street Journal ● Apr. 19, 2026

Inflammatory indicators included C-reactive protein, erythrocyte sedimentation rate, white blood cell count, and platelet count.

From Science Daily ● Apr. 13, 2026

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

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

Once you donate blood, it is taken to a lab, where it is separated into three components: platelets, red blood cells, and plasma.

From Slate ● May 9, 2026

The common thread is that malignant cells overtake the marrow—the tissue that produces white blood cells to fight infection, red blood cells to carry oxygen, and platelets to prevent bleeding.

From The Wall Street Journal ● Apr. 19, 2026

But the study showed that another part of our blood - the platelets that normally stop bleeding - were suppressing the T-cells and making it harder for them to take out the cancer.

From BBC ● Mar. 5, 2025

Antiplatelet drugs are medicines used to prevent strokes and stop platelets from clumping together.

From Science Daily ● Nov. 19, 2024

At some point, you’d have to run into water or rock or the earth’s platelets or something.

From "Gregor the Overlander" by Suzanne Collins

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