Definition of pyrethrin in English:

pyrethrin

noun pʌɪˈriːθrɪn

Chemistry

Any of a group of insecticidal compounds present in pyrethrum flowers.
〔化〕除虫菊酯
pyrethrins can cause allergic reactions
mass noun it contains natural pyrethrin
Example sentencesExamples
- Many of these sprays contain one or more of a group of insecticidal compounds known as pyrethrins.
- These synthetic chemicals mimic the action of natural pyrethrins derived from chrysanthemum flowers.
- If the infestation is severe, topically administered permethrin, pyrethrin, or malathion also may help.
- Citrus-oil products, pyrethrin products, as well as those with pyrethrins and diatomaceous earth, may be effective.
- If you absolutely have to, you can spray with an insecticidal soap or insecticide that contains pyrethrins.

Origin

1920s: from pyrethrum + -in¹.

Definition of pyrethrin in US English:

pyrethrin

noun

Chemistry

Any of a group of insecticidal compounds present in pyrethrum flowers.
〔化〕除虫菊酯
pyrethrins can cause allergic reactions
mass noun it contains natural pyrethrin
Example sentencesExamples
- These synthetic chemicals mimic the action of natural pyrethrins derived from chrysanthemum flowers.
- If the infestation is severe, topically administered permethrin, pyrethrin, or malathion also may help.
- If you absolutely have to, you can spray with an insecticidal soap or insecticide that contains pyrethrins.
- Citrus-oil products, pyrethrin products, as well as those with pyrethrins and diatomaceous earth, may be effective.
- Many of these sprays contain one or more of a group of insecticidal compounds known as pyrethrins.

Origin

1920s: from pyrethrum + -in.

词汇	pyrethrin
释义	Definition of pyrethrin in English: pyrethrin noun pʌɪˈriːθrɪn Chemistry Any of a group of insecticidal compounds present in pyrethrum flowers. 〔化〕除虫菊酯 pyrethrins can cause allergic reactions mass noun it contains natural pyrethrin Example sentencesExamples Many of these sprays contain one or more of a group of insecticidal compounds known as pyrethrins. These synthetic chemicals mimic the action of natural pyrethrins derived from chrysanthemum flowers. If the infestation is severe, topically administered permethrin, pyrethrin, or malathion also may help. Citrus-oil products, pyrethrin products, as well as those with pyrethrins and diatomaceous earth, may be effective. If you absolutely have to, you can spray with an insecticidal soap or insecticide that contains pyrethrins. Origin 1920s: from pyrethrum + -in¹. Definition of pyrethrin in US English: pyrethrin noun Chemistry Any of a group of insecticidal compounds present in pyrethrum flowers. 〔化〕除虫菊酯 pyrethrins can cause allergic reactions mass noun it contains natural pyrethrin Example sentencesExamples These synthetic chemicals mimic the action of natural pyrethrins derived from chrysanthemum flowers. If the infestation is severe, topically administered permethrin, pyrethrin, or malathion also may help. If you absolutely have to, you can spray with an insecticidal soap or insecticide that contains pyrethrins. Citrus-oil products, pyrethrin products, as well as those with pyrethrins and diatomaceous earth, may be effective. Many of these sprays contain one or more of a group of insecticidal compounds known as pyrethrins. Origin 1920s: from pyrethrum + -in.
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