Source : Webster's Revised Unabridged Dictionary (1913)

Cinnamic \Cin*nam"ic\, a. [From {Cinnamon}.] (Chem.)
   Pertaining to, or obtained from, cinnamon.

   {Cinnamic acid} (Chem.), a white, crystalline, odorless
      substance. {C6H5.C2H2C2H2.CO2H}, formerly obtained from
      storax and oil of cinnamon, now made from certain benzene
      derivatives in large quantities, and used for the
      artificial production of indigo.