per·​meth·​rin | \ (ˌ)pər-ˈme-thrən How to pronounce permethrin (audio) \

Definition of permethrin

: a synthetic pyrethroid C21H20Cl2O3 used especially as an insecticide

Examples of permethrin in a Sentence

Recent Examples on the Web Different brands and stores sell permethrin that can be put on the external side of clothing and camping gear. Jordan Mendoza, USA TODAY, 22 Sep. 2021 Until then, as Telford, Klempner, and Aucott reminded me, the best way to stave off Lyme disease is to spray your clothes with the insecticide permethrin, tuck your pants into your socks, and check for ticks after an outing to an infested area. Sue Halpern, The New Yorker, 19 Aug. 2021 Products containing an active ingredient such as acephate (systemic) or permethrin will have a residual effect and can be sprayed on foliage in early May in order to control very high infestations of nymphs. Tim Johnson,, 13 June 2021 Marx recommends treating your clothes and gear with an insecticide that contains at least 0.5 percent permethrin, which is nontoxic to humans. Washington Post, 24 May 2021 Clothing can also be treated with products containing 0.5% permethrin. Beacon-news Staff,, 11 June 2021 Tick activity is expected to be higher than usual this year, and some health experts recommend wearing clothing that’s been treated with permethrin, an insecticide. Washington Post, 3 June 2021 The opposite holds true for permethrin, the most effective treatment for clothing. Larry Olmsted, Forbes, 28 Apr. 2021 Pyrethroids, the family of pesticides that includes permethrin, are extremely toxic to bees and other pollinators. Philip Kiefer, Popular Science, 16 Mar. 2021

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'permethrin.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of permethrin

1975, in the meaning defined above

History and Etymology for permethrin

per- + methyl + pyrethrin

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Time Traveler for permethrin

Time Traveler

The first known use of permethrin was in 1975

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Dictionary Entries Near permethrin

per mensem



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Statistics for permethrin

Last Updated

15 Oct 2021

Cite this Entry

“Permethrin.” Dictionary, Merriam-Webster, Accessed 2 Dec. 2021.

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More Definitions for permethrin


per·​meth·​rin | \ pər-ˈmeth-rən How to pronounce permethrin (audio) \

Medical Definition of permethrin

: a synthetic pyrethroid pesticide C21H20Cl2O3 used especially against insects, ticks, and mites

More from Merriam-Webster on permethrin Encyclopedia article about permethrin


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