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

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.

From Washington Post