- Any of a group of insecticidal compounds present in pyrethrum flowers: pyrethrins can cause allergic reactions [mass noun]: it contains natural pyrethrinMore example sentences
- 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.
- Citrus-oil products, pyrethrin products, as well as those with pyrethrins and diatomaceous earth, may be effective.
More definitions of pyrethrinDefinition of pyrethrin in:
- The US English dictionary