• Webster's Revised Unabridged Dictionary
    • n Pyrethrin (Chem) A substance resembling, and isomeric with, ordinary camphor, and extracted from the essential oil of feverfew; -- called also Pyrethrum camphor.
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Century Dictionary and Cyclopedia
    • n pyrethrin A resinous compound found in pellitory resin from the root of Anacyclus Pyrethrum.
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Webster's Revised Unabridged Dictionary
NL. Pyrethrum, generic name of feverfew, Gr. feverfew


In news:

Research out of Ohio State finds foggers have little impact on modern-day bed bugs due to the brief exposure times, their relatively low concentrations of pyrethrins and/or pyrethroids, and their lack of residual activity.