Coagulation The process of clot formation. Hematoma A localized blood clot in a tissue or organ due to a ruptured blood vessel Thrombus vesse,, An aggregation of platelets and fibrin with entrapment of cellular elements within a blood frequently causing vascular obstruction Hemorrhage Bleeding Hemostasis Arrest of bleedingCoagulation The process of clot formation. Hematoma A localized blood clot in a tissue or organ due to a ruptured blood vessel. Thrombus An aggregation of platelets and fibrin with entrapment of cellular elements within a blood vessel; frequently causing vascular obstruction. Hemorrhage Bleeding. Hemostasis Arrest of bleeding