n.
Pronunciation: p ī - ' r ē -thr ə m, - ' re-
Function: noun
Etymology: Latin, pellitory, from Greek pyrethron, from pyr fire
Date: circa 1543
1 : any of several chrysanthemums with finely divided often aromatic leaves including ornamentals as well as important sources of insecticides
2 : an insecticide made from the dried heads of any of several Old World chrysanthemums (esp. Chrysanthemum cinerariaefolium )