n. [ NL. Pyrethrum, generic name of feverfew, Gr. &unr_; feverfew. ] (Chem.) A substance resembling, and isomeric with, ordinary camphor, and extracted from the essential oil of feverfew; -- called also
n. (Chem.) An alkaloid extracted from the root of the pellitory of Spain (Anacyclus pyrethrum). [ 1913 Webster ]