(ˈ)krō|tänik- noun
Etymology: French crotonique, from New Latin Croton + French -ique -ic
: an unsaturated aliphatic acid CH 3 CH . CHCOOH existing in cis and trans forms; β-methyl-acrylic acid ; especially : the colorless crystalline trans form obtained in the carbonization of wood, made by oxidation of crotonaldehyde, and used chiefly in making synthetic resins and coatings