pyrethrin

American  

[pahy-ree-thrin, -reth-rin] / paɪˈri θrɪn, -ˈrɛθ rɪn /

noun

Chemistry.

1. Also called pyrethrin I.  a viscous, water-insoluble liquid, C 2 1 H 2 8 O 3 , extracted from pyrethrum flowers, used as an insecticide.

2. Also called pyrethrin II.  a like compound, C 2 2 H 2 8 O 5 , obtained and used similarly.

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pyrethrin British  

/ paɪˈriːθrɪn /

noun

1. Also called: pyrethrin I.  an oily water-insoluble compound used as an insecticide. Formula: C 21 H 28 O 3

2. Also called: pyrethrin II.  a compound of similar chemical structure and action, also found in pyrethrum. Formula: C 22 H 28 O 5

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Etymology

Origin of pyrethrin

First recorded in 1830–40; pyrethr(um) + -in ²

Compare meaning

How does pyrethrin compare to similar and commonly confused words? Explore the most common comparisons:

• pyrethrum vs. pyrethrin

Example Sentences

Contact with a single, microscopic pyrethrin droplet can kill an adult mosquito.

From Salon • Oct. 26, 2019

Authorities have sprayed pyrethrin on more than 541,000 acres in recent weeks.

From Washington Times • Oct. 12, 2019

Most of these products have either pyrethrin or a pyrethroid as a main ingredient and those compounds have the same mode of action as DDT, which bed bugs have become resistant to.

From Scientific American • Jan. 23, 2012

Permethrin, found in Nix, is a synthetic pyrethrin with "a long track record of safety," Frankowski said.

From Seattle Times • Sep. 10, 2010

These synthetic chemicals have been fashioned after the natural pyrethrin bug deterrent in chrysanthemums.

From Washington Post • Mar. 8, 2010