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pyrethrin

[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.
Origin
1830-1840
1830-40; pyrethr(um) + -in2
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Based on the Random House Dictionary, © Random House, Inc. 2014.
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Examples for pyrethrin
  • pyrethrin rapidly degrades into less toxic components.
  • Expansion of views on automatic pyrethrin dispensers.
British Dictionary definitions for pyrethrin

pyrethrin

/paɪˈriːθrɪn/
noun
1.
Also called pyrethrin I. an oily water-insoluble compound used as an insecticide. Formula: C21H28O3
2.
Also called pyrethrin II. a compound of similar chemical structure and action, also found in pyrethrum. Formula: C22H28O5
Word Origin
C19: from pyrethrum + -in
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
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