: 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
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
After fibrin formation has occurred, a clot (thrombus) develops.3 This complex process can take seconds to two hours.1
2.
—Michael Menna, Verywell Health, 17 Jan. 2025
In more severe cases, injections such as corticosteroids, platelet-rich plasma (PRP) or fibrin may be necessary.
—Sandra Rose Salathe, Flow Space, 29 Jan. 2025
The body accomplishes this by tightening the blood vessels (vasoconstriction), moving platelets to the injury site (platelet aggregation), and forming fibrin—a protein that helps blood clot.
—Michael Menna, Verywell Health, 17 Jan. 2025
These drugs slow down clotting by reducing fibrin formation and preventing clots from forming and growing.
—Anna Giorgi, Verywell Health, 1 Dec. 2024
The types of products that FDA regulates in this category… [do not include] blood taken from an individual and given back to the same individual as platelet rich fibrin...
—Kara Nesvig, Allure, 15 Aug. 2024
This is filled with fibers made of natural proteins like collagen and fibrin, which are part of the extracellular matrix that gives animal cells their structure.
—Breanna Draxler, Discover Magazine, 2 Apr. 2013
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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
After fibrin formation has occurred, a clot (thrombus) develops.3 This complex process can take seconds to two hours.1
2.
—Michael Menna, Verywell Health, 17 Jan. 2025
In more severe cases, injections such as corticosteroids, platelet-rich plasma (PRP) or fibrin may be necessary.
—Sandra Rose Salathe, Flow Space, 29 Jan. 2025
The body accomplishes this by tightening the blood vessels (vasoconstriction), moving platelets to the injury site (platelet aggregation), and forming fibrin—a protein that helps blood clot.
—Michael Menna, Verywell Health, 17 Jan. 2025
These drugs slow down clotting by reducing fibrin formation and preventing clots from forming and growing.
—Anna Giorgi, Verywell Health, 1 Dec. 2024
The types of products that FDA regulates in this category… [do not include] blood taken from an individual and given back to the same individual as platelet rich fibrin...
—Kara Nesvig, Allure, 15 Aug. 2024
This is filled with fibers made of natural proteins like collagen and fibrin, which are part of the extracellular matrix that gives animal cells their structure.
—Breanna Draxler, Discover Magazine, 2 Apr. 2013
Cite this Entry
“Fibrin.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/fibrin. Accessed 20 Jun. 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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