What does coagulum mean?
A coagulum is a solid or semi-solid mass formed when a liquid coagulates — that is, thickens or clots into a coherent lump. The word is most at home in scientific and technical registers: physicians and hematologists use it for a clotted mass of blood, dairy technologists describe the curd formed when milk is set with rennet as a coagulum, and chemists may apply it to any aggregated mass arising from the coagulation of a colloidal suspension. In ordinary conversation it is rare, with 'clot' and 'curd' doing the everyday work instead. Borrowed directly from Latin, where it meant 'that which has caused to curdle', it belongs to a small family of learned terms — including 'coagulate' and 'coagulation' — all tracing back to the Latin verb 'coagulare', to curdle. Its precise, Latinate character makes it valuable where clarity and formality matter, particularly in medical and laboratory writing.
nounA coagulum is a mass or clot of coagulated matter, especially a clotted mass of blood, milk, or another liquid that has thickened into a semi-solid state.
- A clotted or curdled mass formed from a liquid such as blood or milk.
- More broadly, any coherent solid mass produced by coagulation of a colloidal or particulate suspension.
"Under the microscope, the pathologist identified a firm coagulum blocking the vessel."
"The rennet caused the milk to separate into whey and a soft white coagulum."
"A dark coagulum had formed at the site of the injury, stemming the bleeding."
The Latin plural 'coagula' is standard in scientific and scholarly writing; the anglicized 'coagulums' occurs but is less common.
"Several small coagula were visible on the slide under low magnification."
'Coagulum' is simply Latin for 'that which has curdled' — the same root that gives us both blood clots and cheese curds.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of coagulum
Coagulum comes directly from Latin 'coagulum', meaning 'that which curdles or causes to curdle', derived from the verb 'coagulare' (to curdle), which in turn comes from 'cogere', to drive together or compel. English adopted the word around the early seventeenth century, alongside related borrowings such as 'coagulate' and 'coagulation'. These terms share their root with words like 'cogent', which ultimately descends from the same Latin verb 'cogere'.
Related word forms
How coagulum is actually used
Coagulum is a formal, technical term found chiefly in medicine, biochemistry, food science, and dairy technology; in everyday speech, native speakers almost always say 'clot' or 'curd' instead. It retains its Latin plural 'coagula' in scholarly writing, though 'coagulums' occasionally appears in less formal contexts.
Easily confused with coagulum
'Coagulate' is most commonly a verb meaning to change from a liquid into a thickened mass, while 'coagulum' is strictly a noun naming the resulting solid mass itself.