Definition of pyrethrin in English:

pyrethrin

Syllabification: py·re·thrin
Pronunciation: /pīˈrēTHrən, -ˈreTHrən
 
/

noun

Chemistry
Any of a group of insecticidal compounds present in pyrethrum flowers.
More example sentences
  • Many of these sprays contain one or more of a group of insecticidal compounds known as pyrethrins.
  • These synthetic chemicals mimic the action of natural pyrethrins derived from chrysanthemum flowers.
  • Citrus-oil products, pyrethrin products, as well as those with pyrethrins and diatomaceous earth, may be effective.

Origin

1920s: from pyrethrum + -in1.

Definition of pyrethrin in:

Get more from Oxford Dictionaries

Subscribe to remove adverts and access premium resources

Word of the day anastrophe
Pronunciation: əˈnastrəfi
noun
the inversion of the usual order of words...