pyrethrum

Definition
(noun) made of dried flower heads of pyrethrum plants Definition
(noun) white-flowered pyrethrum of Balkan area whose pinnate leaves are white and silky-hairy below; source of an insecticide; sometimes placed in genus Chrysanthemum Definition
(noun) spring-flowering garden perennial of Asiatic origin having finely divided aromatic leaves and white to pink-purple flowers; source of an insecticide; sometimes placed in genus Chrysanthemum Definition
(noun) used in former classifications for plants later placed in genus Chrysanthemum and now often included in genus Tanacetum