Definition of iodine in English:

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Pronunciation: /ˈʌɪədiːn/
Pronunciation: /ˈʌɪədʌɪn/ Pronunciation: /ˈʌɪədɪn/


[mass noun]
1The chemical element of atomic number 53, a non-metallic element forming black crystals and a violet vapour. (Symbol: I)
Example sentences
  • The halogens are a group of chemical elements that includes fluorine, chlorine, bromine, iodine, and astatine.
  • The chemical element iodine is a major component of thyroid hormones.
  • These can be found through the detection of gases such as sulphur dioxide, hydrogen sulphide, and vapours of mercury, iodine, and radon.
1.1A solution of iodine in alcohol, used as a mild antiseptic.
Example sentences
  • Identify landmarks and prepare the insertion site with iodine or alcohol solution.
  • An iodophor/alcohol prep combines the benefits of iodine and alcohol in a water insoluble film.
  • Apply ethanol, tincture or aqueous solution of iodine, if available.

A member of the halogen group, iodine occurs chiefly as salts in seawater and brines. As a constituent of thyroid hormones it is required in small amounts in the body, and deficiency can lead to goitre.


Early 19th century: from French iode (from Greek iōdēs 'violet-coloured', from ion 'violet' + -eidēs 'like') + -ine4.

For editors and proofreaders

Line breaks: iod¦ine

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