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 (especially Chrysanthemum cinerariaefolium)

Examples of pyrethrum in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Having hit the global market it was abandoned during the 1980s due to the pyrethrum crisis but Fusco documents the journey of this flower and its market return under the Kenyan government in an ambitious attempt to help farmers meet the growing global demand for organic products. Joanne Shurvell, Forbes, 15 Apr. 2021 In 1807, chemists isolated pyrethrum from an Armenian daisy. Carl Zimmer, Discover Magazine, 4 May 2010

Word History

Etymology

Latin, pellitory, from Greek pyrethron, from pyr fire

First Known Use

circa 1543, in the meaning defined at sense 1

Time Traveler
The first known use of pyrethrum was circa 1543

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Cite this Entry

“Pyrethrum.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/pyrethrum. Accessed 25 Mar. 2025.

Kids Definition

1
: any of several chrysanthemums that have finely divided leaves and include ornamental plants as well as important sources of insecticides
2
: an insecticide consisting of the dried heads of some Old World pyrethrums

Medical Definition

1
: any of several chrysanthemums with finely divided often aromatic leaves including ornamentals as well as important sources of insecticides
2
: an insecticide consisting of or derived from the dried heads of any of several Old World chrysanthemums (genus Chrysanthemum of the family Compositae)

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