pyrethrum

American  

[pahy-ree-thruhm, -reth-ruhm] / paɪˈri θrəm, -ˈrɛθ rəm /

noun

1. any of several chrysanthemums, as Chrysanthemum coccineum, having finely divided leaves and showy red, pink, lilac, or white flowers, cultivated as an ornamental.

2. any of several chrysanthemums, as C. cinerariifolium, or C. coccineum, cultivated as a source of insecticides.

3. Pharmacology. the dried flower heads of these plants, used chiefly as an insecticide and sometimes in medicine for certain skin disorders.

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pyrethrum British  

/ paɪˈriːθrəm /

noun

1. any of several cultivated Eurasian chrysanthemums, such as Chrysanthemum coccineum and C. roseum, with white, pink, red, or purple flowers

2. any insecticide prepared from the dried flowers of any of these plants, esp C. roseum

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Etymology

Origin of pyrethrum

First recorded in 1555–65; from Latin, from Greek pýrethron, the name of the flower, akin to pyretós “fever”

Compare meaning

How does pyrethrum compare to similar and commonly confused words? Explore the most common comparisons:

• pyrethrum vs. pyrethrin

Example Sentences

Plus, many other natural repellents—unlike pyrethrum—work by activating multiple odorant receptors, and researchers still know very little about how those other receptors work.

From Scientific American

The Documentary category was won by Vito Fusco, of Italy, for his series on Kenya's pyrethrum flowers, which are used as a natural insecticide.

From BBC

As we head north, Rwanda’s pristine landscape morphs into an undulating canvas of forest, farms and fields of pyrethrum flowers, a cash crop sold as a natural insecticide.

From Washington Post

Seventy-two percent of OTC lice products sold in the United States contain either permethrin or pyrethrum.

From US News

If you’re staying in accommodations that do not have good screens, I recommend getting mosquito nets and clothes impregnated with pyrethrum, a natural insect repellent.

From New York Times