Webster's Revised Unabridged Dictionary · 1913

Thrombus

Thrombus , noun

[New Latin, from Greek {not transcribed} a lump, a clot of blood.]

(a)
(Medicine) A clot of blood formed of a passage of a vessel and remaining at the site of coagulation.
(b)
(Medicine) A tumor produced by the escape of blood into the subcutaneous cellular tissue.