thrombosis

n. formation of a blood clot via a coagulation of the blood in the heart or a blood vessel

Thrombosis is the formation of a clot or thrombus inside a blood vessel, obstructing the flow of blood through the circulatory system. Thromboembolism is a general term describing both thrombosis and its main complication which is embolisation. The term was coined in 1848 by Rudolph Carl Virchow.
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Thrombosis /throm·bo·sis/ the formation or presence of a thrombus.thrombot´ic cerebral thrombosis thrombosis of a cerebral vessel, which may [more]Thrombosis - Community and Resources

Noun
1. the formation or presence of a thrombus (a clot of coagulated blood attached at the site of its formation) in a blood vessel
(hypernym) occlusion
(hyponym) cerebral thrombosis
(part-meronym) thrombus

(n.)
The obstruction of a blood vessel by a clot formed at the site of obstruction; -- distinguished from embolism, which is produced by a clot or foreign body brought from a distance.