Definition of pyrethrum in English:

pyrethrum

Line breaks: pyr|eth¦rum
Pronunciation: /pʌɪˈriːθrəm
 
/

noun

  • 1An aromatic plant of the daisy family, typically having feathery foliage and brightly coloured flowers.
    • Genus Tanacetum (formerly Chrysanthemum or Pyrethrum), family Compositae: several species, in particular T. coccineum, grown as an ornamental, and T. cinerariifolium, grown as a source of the insecticide pyrethrum
    More example sentences
    • Not all herbs smell good - catmint, curry plant, pyrethrum, rue, santolina and tansy are all pretty pongy.
    • Some are derived from plants, such as pyrethrum and neem.
    • When I looked closely I could see the truck had a PyGanic label with the iconic pyrethrum flower on the side.
  • 1.1 [mass noun] An insecticide made from the dried flowers of pyrethrum plants.
    More example sentences
    • By the mid 1800s, the heads of chrysanthemum flowers were used to obtain pyrethrum, and rotenone was extracted from the derris plant.
    • Pesticides that are approved for organic farming include copper, sulfur, petroleum distillates, and pyrethrum.
    • Daisy plants were first used centuries ago as a lice remedy in the Middle East, and this led to the discovery of pyrethrum insecticides.

Origin

Middle English (denoting pellitory): from Latin, from Greek purethron 'feverfew'. The current senses (based on the former genus name) date from the late 19th century.

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