a. (Chem.) Of, pertaining to, or designating, an acid (distinct from santoninic acid) obtained from santonin as a white crystalline substance. [ 1913 Webster ]

n. [ L. herba santonica, a kind of plant, fr. Santoni a people of Aquitania; cf. Gr. &unr_;: cf. F. santonine. ] (Chem.) A white crystalline substance having a bitter taste, extracted from the buds of levant wormseed and used as an anthelmintic. It occassions a peculiar temporary color blindness, causing objects to appear as if seen through a yellow glass. [ 1913 Webster ]

n. (Chem.) A salt of santoninic acid. [ 1913 Webster ]

a. (Chem.) Of or pertaining to santonin; -- used specifically to designate an acid not known in the free state, but obtained in its salts. [ 1913 Webster ]