'Cinnamic acid' definitions:

Definition of 'Cinnamic acid'

From: GCIDE

Cinnamic \Cin*nam"ic\, a. [From Cinnamon.] (Chem.) Pertaining to, or obtained from, cinnamon. [1913 Webster]
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. [1913 Webster]