What does clotting mean?
Clotting is the process by which a fluid — most importantly blood — thickens into a semisolid mass known as a clot. In the human body, clotting (also called coagulation) is a vital protective mechanism: when a vessel is injured, a cascade of proteins and platelets transforms liquid blood into a gel-like plug that seals the wound and halts bleeding. Because this process can go awry, 'clotting' features heavily in medical language, appearing in terms such as clotting factors, clotting time, and clotting disorders; unwanted clotting inside vessels can cause heart attacks and strokes, while impaired clotting underlies conditions like haemophilia. Beyond medicine, the word describes any similar thickening of liquids, such as milk curdling. Derived ultimately from the Middle English noun 'clot', the word carries a precise, clinical tone and is essential vocabulary for understanding both healing and disease.
nounThe process by which a liquid, especially blood, thickens and forms a semisolid mass or clot. In medicine it refers specifically to coagulation, the mechanism that stops bleeding.
- The process of blood coagulating to form a semisolid mass that stops bleeding (the dominant sense).
- More generally, the thickening or congealing of any liquid into a clotted mass, e.g. milk curdling.
"Doctors monitored the patient's blood clotting closely after the surgery to prevent dangerous blockages."
"Aspirin works by interfering with platelets, thereby slowing the blood's clotting response."
"The cold morning left the cream with a slight clotting at the top of the bottle."
Your body runs a clotting cascade of more than a dozen proteins — miss just one clotting factor, as in haemophilia, and a small cut can become life-threatening.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of clotting
The word derives from 'clot', a noun attested in Middle English (from around the 13th–14th century), probably of Germanic origin and related to words meaning a rounded lump or mass, such as 'clump' and possibly 'clog'. 'Clotting' arose as the verbal noun of the verb 'to clot', which developed from the noun in later English. Its Germanic roots make it distinct from the Latinate synonym 'coagulation', which entered scientific English via Latin 'coagulare'.
How clotting is actually used
Predominantly used in medical and scientific registers; 'clotting' is the standard term in clinical contexts such as 'clotting factors' and 'clotting disorders', while 'coagulation' is the more technical synonym favoured in laboratory settings. Outside medicine it appears mainly in discussions of dairy products congealing.
Easily confused with clotting
Clouting means hitting someone or patching with cloth, whereas clotting refers to the formation of clots; the two differ by one letter but share nothing in meaning.