a. (Chem.) Valerianic; specifically, designating any one of three metameric acids, of which the typical one (called also inactive valeric acid), C4H9CO2H, is obtained from valerian root and other sources, as a corrosive, mobile, oily liquid, having a strong acid taste, and an odor of old cheese. [ 1913 Webster ]

Active valeric acid, a metameric variety which turns the plane of polarization to the right, although formed by the oxidation of a levorotatory amyl alcohol. [ 1913 Webster ]