heparin

hep·a·rin

noun \ˈhep-ə-rən\

Definition of HEPARIN

: a glycosaminoglycan sulfuric acid ester that occurs especially in the liver and lungs, that prolongs the clotting time of blood by preventing the formation of fibrin, and that is administered parenterally in the form of its sodium salt in vascular surgery and in the treatment of postoperative thrombosis and embolism—see liquaemin; compare antiprothrombin, antithrombin