tonka bean(n = noun.plant) coumara nut - fragrant black nutlike seeds of the tonka bean tree; used in perfumes and medicines and as a substitute for vanilla;
The seed of a leguminous tree (Dipteryx odorata), native of Guiana. It has a peculiarly agreeable smell, and is employed in the scenting of snuff. Called also tonquin bean. [1913 Webster]