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per·meth·rin

(pər-mĕthrĭn)

A synthetic pyrethroid, C₂₁H₂₀Cl₂O₃, used as an agricultural, industrial, and residential insecticide, to treat scabies and head lice in humans, and to control fleas and ticks in dogs.

[PER- + (res)methrin, a pyrethroid (resm-, of unknown origin + (PYR)ETHRIN).]

Indo-European & Semitic Roots Appendices

Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:

Indo-European Roots

Semitic Roots

The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.

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