permethrin

P3E1R1M3E1T1H4R1I1N1

noun

A synthetic insecticide, C₂₁H₂₀Cl₂O₃, used to treat head lice, nits, and scabies; as an active ingredient in flea collars; and to eradicate woodworm infestations.

OriginLatin perme(ō) ← Proto-Italic *mejo- ← Proto-Indo-European *mey-o- →
UncommonScrabble 17
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Meanings

nounpermethrin (countable and uncountable, plural permethrins)

plural permethrins

  1. countableuncountableA synthetic insecticide, C₂₁H₂₀Cl₂O₃, used to treat head lice, nits, and scabies; as an active ingredient in flea collars; and to eradicate woodworm infestations.

    *Permethrin is the artificial version of pyrethrin, which is made from chrysanthemum flowers.

    2023, translated in 2025, Berta Páramo and translated by Marc Correa Haro, Lice: How to Survive on Humans, page 152

Origin

  1. Proto-Indo-European*per-
  2. Proto-Italic*peri-
  3. Latinper-
  4. Proto-Indo-European*mey-
  5. Proto-Indo-European*mey-o-
  6. Proto-Italic*mejo-
  7. Latinmeō
  8. Latinperme(ō)
  9. Englishpermethrin

From Latin perme(ō) (“to pervade”) + English -thrin.

Full word history & related roots →
Cite this entry
APA

permethrin. (n.d.). In WatkinsX Dictionary. Retrieved November 2, 2026, from https://dictionary.watkinsx.com/word/permethrin

MLA

“permethrin.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/permethrin. Accessed November 2, 2026.

Chicago

WatkinsX Dictionary, s.v. “permethrin,” accessed November 2, 2026, https://dictionary.watkinsx.com/word/permethrin.

Source: permethrin on Wiktionary, CC BY-SA 4.0.