Definition of fluoride in English:

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Pronunciation: /ˈflʊərʌɪd/
Pronunciation: /ˈflɔːrʌɪd/


1 Chemistry A compound of fluorine with another element or group, especially salt of the anion F or an organic compound with fluorine bonded to an alkyl group.
Example sentences
  • Highly substituted alkyl fluorides, perfluoroalkanes, are now used as artificial blood substitutes because of their oxygen transporting properties.
  • What Sanpaolesi had aimed to do was to consolidate the deteriorated surface of the marble by forming a layer of calcium, zinc and magnesium fluorides and silica gel on the marble surface.
  • Many elements form fluorides, however, that cannot be labeled covalent or ionic; these halides exhibit the characteristics of polymeric compounds.
2 [mass noun] Sodium fluoride or another fluorine-containing salt added to water supplies or toothpaste in order to reduce tooth decay.
Example sentences
  • Like all the other dentists, Lester had learnt in dental school that fluoride reduces tooth decay.
  • There is overwhelming evidence that fluoride can substantially reduce tooth decay.
  • Use fluoride toothpaste as fluoride makes teeth stronger and more resistant to acid attacks.


Early 19th century: from fluorine + -ide.

For editors and proofreaders

Line breaks: fluor|ide

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