Definition of pyrethrin in English:

pyrethrin

Line breaks: pyr|eth¦rin
Pronunciation: /pʌɪˈriːθrɪn
 
/

noun

Chemistry
  • Any of a group of insecticidal compounds present in pyrethrum flowers: pyrethrins can cause allergic reactions [mass noun]: it contains natural pyrethrin
    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.

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