pyrethrin

noun

py·​re·​thrin pī-ˈrē-thrən  -ˈre- 

: either of two oily liquid esters C₂₁H₂₈O₃ and C₂₂H₂₈O₅ having insecticidal properties and occurring especially in the flowers of pyrethrum

Examples of pyrethrin in a Sentence

Recent Examples on the Web

Often cited in grub control lists, Williams explains that this classic flower contains potent insecticidal pyrethrins in its flower heads. — Sj McShane, Martha Stewart, 11 July 2026

Look for products containing ingredients such as pyrethrin, bifenthrin, or carbaryl. — Nafeesah Allen, Better Homes & Gardens, 9 July 2026

He was covered from neck to boots in fabrics soaked with permethrin—a pesticide modelled on the toxic pyrethrin found in chrysanthemum flowers. — Burkhard Bilger, New Yorker, 29 June 2026

Systemic Insecticide Insecticide sprays that contain bifenthrin, cyfluthrin, lambda cyhalothrin, malathion, permethrin, or pyrethrin will control aphids. — Mary Marlowe Leverette, Southern Living, 20 May 2026

Word History

Etymology

International Scientific Vocabulary, from Latin pyrethrum

First Known Use

1882, in the meaning defined above

Medical Definition

pyrethrin

noun

py·​re·​thrin pī-ˈrē-thrən  -ˈreth-rən 

: either of two oily liquid esters C₂₁H₂₈O₃ and C₂₂H₂₈O₅ that have insecticidal properties and are the active components of pyrethrum