[pahy-ree-thruh
m, -reth-ruhm] 
| 1. | any of several chrysanthemums, as Chrysanthemum coccineum, having finely divided leaves and showy red, pink, lilac, or white flowers, cultivated as an ornamental. |
| 2. | any of several chrysanthemums, as C. cinerariifolium, or C. coccineum, cultivated as a source of insecticides. |
| 3. | Pharmacology. the dried flower heads of these plants, used chiefly as an insecticide and sometimes in medicine for certain skin disorders. |
| py·re·thrum (pī-rē'thrəm, -rěth'rəm) n.
[Latin, pellitory, from Greek purethron, feverfew, from pūr, fire (from its warming effect); see pyretic.] |
