- a slightly water-soluble, poisonous compound, C5H8O2, derived from croton oil and occurring as a thick, syrupy liquid or in colorless crystals.
- a syrupy liquid or crystalline colourless unsaturated carboxylic acid, with the trans- configuration, found in croton oil and used in perfumery; trans- 2-methyl-2-butenoic acid. Formula: CH 3 CH:C(CH 3)COOH
