What is "cinnamic acid"

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.

n. (context organic compound English) The aromatic carboxylic acid C₆H₅-CH=CH-COOH obtained from cinnamon; it is used in perfumery etc

Cinnamic acid is an organic compound with the formula CHCHCHCOH. It is a white crystalline compound that is slightly soluble in water, and freely soluble in many organic solvents. Classified as an unsaturated carboxylic acid, it occurs naturally in a number of plants. It exists as both a cis and a trans isomer, although the latter is more common.