: a white insoluble fibrous protein formed from fibrinogen by the action of thrombin especially in the clotting of blood
Examples of fibrin in a Sentence
Recent Examples on the Web
The clot, or thrombus, is made of fibrin, platelets, white blood cells and some red blood cells.
—
Daryl Austin, USA Today, 15 Aug. 2025
Innovations include: Platelet-rich fibrin (PRF): A patient's blood platelets are concentrated and applied to promote healing in gum and bone tissue.
—Ximena Araya-Fischel, Forbes.com, 4 July 2025
Areas to watch, says Arthur Adam, a neurosurgeon and stroke expert at University of Tennessee Health Sciences Center, include how human brain tissue is affected by the new thrombectomy method, and how the cells and debris behave once they’re liberated from the fibrin by the milli-spinner.
—Ani Freedman, Fortune, 27 June 2025
When mixed, the two form a fibrin network, mimicking the body's natural healing process.
—Lucy Notarantonio, MSNBC Newsweek, 18 June 2025
Blood clots are clumped together by thread-like proteins called fibrin.
—Melissa Rudy, FOXNews.com, 16 June 2025
Existing clot-removal treatments typically involve inserting a device into the affected blood vessel via a catheter, then using that device to either suck up the fibrin clump or snare it then drag it out.
—Ben Coxworth, New Atlas, 7 June 2025
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Daryl Austin, USA Today, 15 Aug. 2025
Innovations include: Platelet-rich fibrin (PRF): A patient's blood platelets are concentrated and applied to promote healing in gum and bone tissue.
—Ximena Araya-Fischel, Forbes.com, 4 July 2025
Areas to watch, says Arthur Adam, a neurosurgeon and stroke expert at University of Tennessee Health Sciences Center, include how human brain tissue is affected by the new thrombectomy method, and how the cells and debris behave once they’re liberated from the fibrin by the milli-spinner.
—Ani Freedman, Fortune, 27 June 2025
When mixed, the two form a fibrin network, mimicking the body's natural healing process.
—Lucy Notarantonio, MSNBC Newsweek, 18 June 2025
Blood clots are clumped together by thread-like proteins called fibrin.
—Melissa Rudy, FOXNews.com, 16 June 2025
Existing clot-removal treatments typically involve inserting a device into the affected blood vessel via a catheter, then using that device to either suck up the fibrin clump or snare it then drag it out.
—Ben Coxworth, New Atlas, 7 June 2025
Cite this Entry
“Fibrin.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/fibrin. Accessed 31 Oct. 2025.
Copy CitationKids Definition
fibrin
noun
fi·brin
ˈfī-brən 
: a white fibrous substance that is difficult to dissolve and is formed in the clotting of the blood
Medical Definition
fibrin
noun
fi·brin
ˈfī-brən
: a white insoluble fibrous protein formed from fibrinogen by the action of thrombin especially in the clotting of blood
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