pyrethrum

Pyrethrum has 3 syllables: py · re · thrum.

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.

noun. Used in former classifications for plants later placed in genus Chrysanthemum and now often included in genus Tanacetum.

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.

noun. Made of dried flower heads of pyrethrum plants.