Chem. [a. F. coumarine, f. coumarou = cumarú, native name in Guiana of the Tonka bean + -IN.] A crystalline substance (C9 H6 O2), with aromatic odor, found in the seeds of the cumarú, coumarou, or Tonka bean; also in melilot, woodruff, sweet-scented vernal grass, etc.

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1830.  Lindley, Nat. Syst. Bot., 92. The volatile oil of the Coumarouma odorata, or Tonka Bean, has been ascertained to be a peculiar principle called Coumarin.

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1882.  J. Smith, Dict. Econ. Plants, 136. It is probable that hay-fever … may be attributed to the coumarin in the atmosphere.

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  Hence Coumaric a., in coumaric acid, an acid (C9 H8 O3) obtained from coumarin; Coumarate, a salt of coumaric acid.

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1863–72.  Watts, Dict. Chem., II. 93. Coumaric acid decomposes carbonates. The formula of the coumarates is C9 H7 O2 . M.

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