What does platelet mean?
A platelet is a tiny, disc-shaped fragment formed from a cell in the bone marrow. These fragments circulate in the blood and are essential for clotting: when a blood vessel is damaged, platelets adhere to the injured surface, become activated, and help produce a clot that limits blood loss. The word is common in medical discussions of bleeding disorders, laboratory blood counts, transfusion, and cardiovascular medicine. A platelet count measures the number of platelets in a blood sample; a low count can increase the risk of bruising or bleeding, while a high count may sometimes be associated with unwanted clotting. Although often casually called a blood cell, a platelet is technically a cell fragment rather than a complete cell. The familiar term combines the idea of a small, flat body with the word's long medical history.
nounA platelet is a small, flat fragment of a blood cell involved in blood clotting. Platelets help damaged blood vessels form clots and stop bleeding.
- A small, flat blood-cell fragment that participates in blood clotting and helps repair damaged blood vessels.
"The blood test revealed a low platelet count, so the doctor ordered further tests."
"Platelets gathered at the site of the injury and helped form a clot."
"Patients with very low platelet levels may bruise or bleed easily."
The standard plural is platelets.
"The patient's platelets were monitored closely during treatment."
A platelet is not a complete cell but a tiny fragment of one of the body's most important clotting tools.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does platelet come from?
The word platelet was formed from the Greek adjective platys, meaning broad or flat, together with the diminutive suffix -let, literally suggesting a small flat body. It was used in medical terminology before or alongside the development of its familiar modern reference to blood-clotting fragments. The same Greek element appears in related words such as platypus and Plato, while the broader English combining form platy- continues to mean broad or flat.
Related word forms
How platelet is actually used
The term is standard in medicine and biology. In general contexts, it is usually used in the singular for the blood component and in the plural when referring to counts or collections of them.
Easily confused with platelet
A thrombocyte is a blood platelet, especially in technical usage; platelet is the more common everyday term.