pyrethrin

[pahy-ree-thrin, -reth-rin]

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.

pyrethrin

/ 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

Word History and Origins

Origin of pyrethrin¹

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

Word History and Origins

Origin of pyrethrin¹

C19: from _pyrethrum + _-in

Example Sentences

The team also used chemical analysis to determine how two of pyrethrum’s molecular components—EBF and pyrethrin—elicit the repellent response.

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Although each product has the same effect on insects — and presents the same risks to beneficial insects — pyrethrin usually is more potent and lasts longer.

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It’s the naturally derived form of pyrethrin, which, like boric acid, is deadly to insects, but has very low toxicity to humans and other mammals.

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Pyrethrum is extracted from chrysanthemum flowers; pyrethrin is created in a lab.

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Pyrethrin and its synthetic derivatives are used in garden insecticides, pet sprays, mosquito repellents and lice shampoos.

Read more on New York Times