noun
: a globulin occurring in inactive form in blood plasma that in its active form is one of the factors accelerating the formation of thrombin from prothrombin in the clotting of blood
noun
: a globulin occurring in inactive form in blood plasma that in its active form is one of the factors accelerating the formation of thrombin from prothrombin in the clotting of blood
Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012