coumarin

cou·ma·rin

noun \ˈkü-mə-rən\

Definition of COUMARIN

: a toxic white crystalline lactone C₉H₆O₂ with an odor of new-mown hay found in plants or made synthetically and used especially in perfumery and as the parent compound in various anticoagulant agents (as warfarin); also : a derivative of this compound