\Cou"ma*rin\ (k[=oo]"m[.a]*r[i^]n), n. [F., fr.
coumarou, a tree of Guiana.] (Chem.)
The concrete essence of the tonka bean, the fruit of
{Dipterix (formerly Coumarouna) odorata} and consisting
essentially of coumarin proper, which is a white crystalline
substance, {C9H6O2}, of vanilla-like odor, regarded as an
anhydride of coumaric acid, and used in flavoring. Coumarin
in also made artificially.