Natural insecticide made from the blossoms of various chrysanthemums.
Merriam-Webster Online Dictionary
pyrethrum (noun)1.
any of several chrysanthemums with finely divided often aromatic leaves including ornamentals as well as important sources of insecticides
2.
an insecticide made from the dried heads of any of several Old World chrysanthemums (especially ) - Chrysanthemum cinerariaefolium
Pyrethrum (Wikipedia)
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Pyrethrum was a genus of several Old World plants now classified in either Chrysanthemum or Tanacetum which are cultivated as ornamentals for their showy flower heads. Pyrethrum continues to be used as a common name for plants formerly included in the genus Pyrethrum. Pyrethrum is also the name of a natural insecticide made from the dried flower heads of Chrysanthemum cinerariifolium and Chrysanthemum coccineum. The insecticidal compounds present in these species are pyrethrins.
Pyrethrum (Wiktionary)
English
Etymology
From Old English pyretre, from (and later reformed after) Latin pyrethrum (in Pliny), from Hellenistic Ancient Greek πύρεθρον (púrethron).
Pronunciation
- (US) IPA(key): /paɪˈɹiθɹəm/
Noun
pyrethrum (countable and uncountable, plural pyrethrums)
- Any of several daisy-like perennial African plants of the genus Tanacetum, especially Tanacetum cinerariifolium. [from 10th c.]
- Anacyclus pyrethrum (pellitory of Spain)
- (organic chemistry
Chrysanthemum cinerariifolium, Chrysanthemum coccineum, Tanacetum cinerariifolium, Tanacetum coccineum, Dalmatian chrysanthemum