*crotonic*

a. Of or pertaining to, or derived from, a plant of the genus Croton, or from croton oil. [ 1913 Webster ]

Crotonic acid (Chem.), a white crystalline organic acid, C3H5.CO2H, of the ethylene, or acrylic acid series. It was so named because formerly supposed to exist in croton oil. Also, any acid metameric with crotonic acid proper. [ 1913 Webster ]

☞ The acid characteristic of croton oil is tiglic or tiglinic acid, a derivative of crotonic acid. [ 1913 Webster ]