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iodine

noun, often attributive
io·​dine | \ ˈī-ə-ˌdīn How to pronounce iodine (audio) , -dᵊn, -ˌdēn\

Definition of iodine

1 : a nonmetallic halogen element obtained usually as heavy shining blackish-gray crystals and used especially in medicine, photography, and analysis — see Chemical Elements Table
2 : a tincture of iodine used especially as a topical antiseptic
Did You Know? Example Sentences Learn More about iodine

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Did You Know?

Iodine is a nonmetallic chemical element and the heaviest nonradioactive halogen. It is a very nearly black crystalline solid that can turn to a deep violet, irritating vapor. In nature it is never found uncombined, and occurs mostly in brines and seaweeds. Dietary iodine is essential for thyroid gland function, so table salt usually has potassium iodide added to prevent iodine deficiency. Elemental iodine is used in medicine, in synthesizing some organic chemicals, in manufacturing dyes, in analytical chemistry, and in photography. The radioactive isotope I-131, with an eight-day half-life, is very useful in medicine and other applications.

Examples of iodine in a Sentence

Recent Examples on the Web

 Emergency officials issued a warning to all workers to stay indoors and close the windows, while fearful residents rushed to buy iodine pills, which can help limit the damage from exposure to radiation. — Fox News, "Russia cancels evacuation after missile explosion, claims tests show radiation levels 'normal'," 14 Aug. 2019 But state law requires only active plants to cover the costs of state oversight, from monitoring the air for radioactive particles to maintaining fresh stocks of iodine pills in case of a meltdown. — David Abel, BostonGlobe.com, "Pilgrim no longer required to pay state for regulatory costs," 9 Aug. 2019 Frightened residents rushed to buy iodine, which can help reduce risks from exposure to radiation. — Vladimir Isachenkov, chicagotribune.com, "The mysterious explosion in Russia involving a ‘Skyfall’ nuclear missile that’s evoking memories of Chernobyl," 14 Aug. 2019 Frightened residents rushed to buy iodine, which can help reduce risks from exposure to radiation. — Washington Post, "Mysterious missile explosion in Russia raises questions," 14 Aug. 2019 News of the explosion set off in nearby cities and towns a run on iodine, a form of which is believed to help prevent the thyroid gland from absorbing radiation. — oregonlive.com, "Russia says new weapon blew up in nuclear accident last week," 12 Aug. 2019 News of the explosion set off in nearby cities and towns a run on iodine, which is believed to help prevent the thyroid gland from absorbing radiation. — Author: Jake Rudnitsky, Stepan Kravchenko, Anchorage Daily News, "Small nuclear reactor blew up in accident that killed five scientists, Russia says," 12 Aug. 2019 News of the explosion set off in nearby cities and towns a run on iodine, which is believed to help prevent the thyroid gland from absorbing radiation. — Jake Rudnitsky And Stepan Kravchenko / Bloomberg, Time, "Russia Says Small Nuclear Reactor Blew Up in Deadly Accident," 12 Aug. 2019 Local media has also reported that local residents have been stocking up on iodine, which helps to reduce the effects of radiation exposure. — Fox News, "Russia nuclear agency says 5 dead in missile test explosion," 11 Aug. 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'iodine.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of iodine

1814, in the meaning defined at sense 1

History and Etymology for iodine

French iode "iodine" (borrowed from Greek ioeidḗs "violet-colored," from íon "the color violet"—going back to *wion, akin to the source of Latin viola "the violet flower"— + -o-eidēs -oid entry 2) + -ine entry 2 (after chlorine, fluorine) — more at violet

Note: The French word iode was apparently introduced by the chemists Bernard Courtois (1777-1838) and Joseph Louis Gay-Lussac (1778-1850); cf. B. Courtois, "Découverte d'une substance nouvelle dans le Vareck," Annales de chimie, tome 88 (1813), p. 305: "La substance nouvelle, que depuis on a nommé iode à cause de la belle couleur violette de sa vapeur, a bien tout l'aspect d'un métal." ("The new substance, which since has been named iode because of the beautiful violet color of its vapor, has all the appearance of a metal.") Note that a borrowing from Greek ioeidḗs should properly have yielded ioïde in French rather than iode; the direct source of the latter may have been iṓdēs "rust-colored," a derivative of íos "rust, verdigris," taken erroneously to be a derivative of íon "the color violet."

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More Definitions for iodine

iodine

noun
How to pronounce iodine (audio)

English Language Learners Definition of iodine

: a chemical element that is used especially in medicine and photography

See the full definition for iodine in the English Language Learners Dictionary

iodine

noun
io·​dine | \ ˈī-ə-ˌdīn How to pronounce iodine (audio) , -dᵊn\

Kids Definition of iodine

1 : a chemical element found in seawater and seaweeds and used especially in medicine and photography
2 : a solution of iodine in alcohol used to kill germs

iodine

noun, often attributive
io·​dine | \ ˈī-ə-ˌdīn How to pronounce iodine (audio) , -əd-ᵊn How to pronounce iodine (audio) , -ə-ˌdēn How to pronounce iodine (audio) \

Medical Definition of iodine

1 : a nonmetallic halogen element obtained usually as heavy shining blackish gray crystals and used especially in medicine (as in antisepsis and in the treatment of goiter and cretinism) and in photography and chemical analysis —symbol I — see Chemical Elements Table
2 : a tincture of iodine used especially as a topical antiseptic

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