D defs.my
Entry 1 sense Webster, 1913

Coumarin

/(ko͞o"mȧ*rĭn)/ · Cou·ma·rin · IPA /ˈkuːməɹɪn/
01 n. The concrete essence of the tonka bean, the fruit of Dipterix (formerly Coumarouna) odorata and consisting essentially of coumarin proper, …
  1. 1.
    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.(Chem.)