: a minute flattened body (as of ice or a mineral)
especially
: a minute colorless disklike body of mammalian blood that assists in blood clotting by adhering to other platelets and to damaged epithelium
called also blood platelet, thrombocyte
Examples of platelet in a Sentence
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The virus appears to trigger a destructive host response in which infected endothelium, immune activation, platelets, coagulation, cytokine signaling, and complement converge to destabilize the vascular barrier.
—
Steve Brozak, Forbes.com, 15 May 2026
Other possible complications involve hyponatremia, in which sodium levels in the blood drop too low, metabolic alkalosis, in which acid levels become unbalanced, and hemolytic uremic syndrome, in which red blood cells and platelets are destroyed.
—Don Sweeney
april 14, Sacbee.com, 14 Apr. 2026
Platelet-rich plasma microneedling Platelet-rich plasma involves drawing blood, separating out the platelets, and applying it topically to your face during and after microneedling.
—Erica Sweeney, Time, 9 Apr. 2026
This serum uses a concentrated extract from platelets that features growth factors and bioactive proteins — not unlike what’s used in PRP therapy — to stimulate hair growth at the follicle level.
—Rebecca Strong, USA Today, 3 Apr. 2026
See All Example Sentences for platelet
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Steve Brozak, Forbes.com, 15 May 2026
Other possible complications involve hyponatremia, in which sodium levels in the blood drop too low, metabolic alkalosis, in which acid levels become unbalanced, and hemolytic uremic syndrome, in which red blood cells and platelets are destroyed.
—Don Sweeney
april 14, Sacbee.com, 14 Apr. 2026
Platelet-rich plasma microneedling Platelet-rich plasma involves drawing blood, separating out the platelets, and applying it topically to your face during and after microneedling.
—Erica Sweeney, Time, 9 Apr. 2026
This serum uses a concentrated extract from platelets that features growth factors and bioactive proteins — not unlike what’s used in PRP therapy — to stimulate hair growth at the follicle level.
—Rebecca Strong, USA Today, 3 Apr. 2026
See All Example Sentences for platelet
Cite this Entry
“Platelet.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/platelet. Accessed 21 May. 2026.
Copy CitationKids Definition
platelet
noun
plate·let
ˈplāt-lət 
: one of the tiny colorless disk-shaped bodies of the blood of mammals that assist in blood clotting
Medical Definition
platelet
noun
plate·let
ˈplāt-lət
: a minute colorless anucleate disklike body of mammalian blood that is derived from fragments of megakaryocyte cytoplasm, that is released from the bone marrow into the blood, and that assists in blood clotting by adhering to other platelets and to damaged epithelium
called also blood platelet, thrombocyte
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