pyrethrin(redirected from pyrethrin I)
Also found in: Medical, Encyclopedia.
Either of two viscous liquid esters, C21H28O3 or C22H28O5, that are extracted from pyrethrum flowers and used as insecticides.
1. (Elements & Compounds) Also called: pyrethrin I an oily water-insoluble compound used as an insecticide. Formula: C21H28O3
2. (Elements & Compounds) Also called: pyrethrin II a compound of similar chemical structure and action, also found in pyrethrum. Formula: C22H28O5
[C19: from pyrethrum + -in]
py•re•thrin(paɪˈri θrɪn, -ˈrɛθ rɪn)
either of two chemicals, C21H28O3 or C22H28O5, extracted from pyrethrum flowers: used as an insecticide.