pyrethroid
noun
py·re·throid
pī-ˈrē-ˌthrȯid 
-ˈre-
-ˈre-
: any of various synthetic compounds that are related to the pyrethrins and resemble them in insecticidal properties
pyrethroid
adjective
Examples of pyrethroid in a Sentence
Recent Examples on the Web
The synthetic pyrethroid insecticide cypermethrin, which the EPA calls a possible human carcinogen, was detected on nearly half of all samples.
—
Sandee Lamotte, CNN Money, 9 June 2026
The North Carolina State Extension recommends liquid residual pyrethroid insecticides applied to areas where spiders are seen or suspected.
—Eva Flowe
may 28, Charlotte Observer, 28 May 2026
This includes fipronil, boric acid or borax, pyrethroids, hydramethylnon, imidacloprid and thiamethoxam.
—Bestreviews, Chicago Tribune, 19 May 2026
Large pest control companies typically use insecticides with synthetic pyrethroids and insect growth regulators (like pyriproxyfen).
—Alora Bopray, USA Today, 1 Apr. 2026
See All Example Sentences for pyrethroid
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Sandee Lamotte, CNN Money, 9 June 2026
The North Carolina State Extension recommends liquid residual pyrethroid insecticides applied to areas where spiders are seen or suspected.
—Eva Flowe
may 28, Charlotte Observer, 28 May 2026
This includes fipronil, boric acid or borax, pyrethroids, hydramethylnon, imidacloprid and thiamethoxam.
—Bestreviews, Chicago Tribune, 19 May 2026
Large pest control companies typically use insecticides with synthetic pyrethroids and insect growth regulators (like pyriproxyfen).
—Alora Bopray, USA Today, 1 Apr. 2026
See All Example Sentences for pyrethroid
Cite this Entry
“Pyrethroid.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/pyrethroid. Accessed 18 Jun. 2026.
Copy CitationMedical Definition
pyrethroid
noun
py·re·throid
pī-ˈrē-ˌthrȯid
-ˈreth-ˌrȯid
-ˈreth-ˌrȯid
: any of various synthetic compounds that are related to the pyrethrins and resemble them in insecticidal properties
pyrethroid
adjective
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