iodine

noun, often attributive io·dine \ ˈī-ə-ˌdīn , -dᵊn , -ˌdēn \
Updated on: 16 Nov 2017

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

Recent Examples of iodine from the Web

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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.

Origin and Etymology of 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 2-oid) + 2-ine (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."


IODINE Defined for English Language Learners

iodine

noun

Definition of iodine for English Language Learners

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


IODINE Defined for Kids

iodine

noun io·dine \ ˈī-ə-ˌdīn , -dᵊn \

Definition of iodine for Students

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

Medical Dictionary

iodine

noun, often attributive io·dine \ ˈī-ə-ˌdīn , -əd-ᵊn , -ə-ˌdēn \

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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