iodine

[ ahy-uh-dahyn, -din; in Chemistry also ahy-uh-deen ]

/ ˈaɪ əˌdaɪn, -dɪn; in Chemistry also ˈaɪ əˌdin /

noun Chemistry.

a nonmetallic halogen element occurring at ordinary temperatures as a grayish-black crystalline solid that sublimes to a dense violet vapor when heated: used in medicine as an antiseptic. Symbol: I; atomic weight: 126.904; atomic number: 53; specific gravity: (solid) 4.93 at 20°C.

Nearby words

Also i·o·din

[ahy-uh-din] /ˈaɪ ə dɪn/.

Origin of iodine

1814; < French iode (< Greek īṓdēs, orig. rust-colored, but by folk etymology taken as í(on) violet + -ōdēs -ode¹) + -ine²; introduced by H. Davy

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for iodine

They said this phenomenon might have caused the level of iodine to rise before the tap water could reach the purifying plant.
Radiation in Tokyo's Tap Water|Lennox Samuels|March 23, 2011|DAILY BEAST
At Chernobyl, iodine fell on the grass, cows ate the grass, and people drank the milk.
California's Nuclear Freakout|Josh Dzieza, Tricia Romano|March 18, 2011|DAILY BEAST
The iodine plume itself is not the issue, agreed Brenner, but that it falls on the grass and cows eat it.
California's Nuclear Freakout|Josh Dzieza, Tricia Romano|March 18, 2011|DAILY BEAST
Even at the Chernobyl meltdown in 1986, he pointed out, cesium and iodine were the problem.
The Toxic Fuel Inside Japan's Nuclear Plant|Eve Conant|March 15, 2011|DAILY BEAST

One of the isotopes of fission products, when fuel melts, is an iodine isotope, and it goes in your body through your thyroid.
Japan Nuclear Fallout: How Bad Could It Get?|Josh Dzieza|March 12, 2011|DAILY BEAST
Several officers got very sore eyes, and the only thing to do with a scratch was to dab it with iodine at once.
A Prisoner in Turkey|John Still
The presence of starch can be shown by testing with a solution of iodine.
Outlines of Lessons in Botany, Part I; From Seed to Leaf|Jane H. Newell
Toward the centre of the cell, especially if it has first been treated with iodine, the nucleus may be found.
Elements of Structural and Systematic Botany|Douglas Houghton Campbell
We have already learned that iodine turns starch this color, so we conclude that leaves must contain starch.
The First Book of Farming|Charles L. Goodrich
A far-sighted person would have foreseen other results from the mixture beside the chemical action of the iodine on the starch.
The Camp Fire Girls' Larks and Pranks|Hildegard G. Frey

British Dictionary definitions for iodine

iodine

/ (ˈaɪəˌdiːn) /

noun

a bluish-black element of the halogen group that sublimates into a violet irritating gas. Its compounds are used in medicine and photography and in dyes. The radioisotope iodine-131 (radioiodine), with a half-life of 8 days, is used in the diagnosis and treatment of thyroid disease. Symbol: I; atomic no: 53; atomic wt: 126.90447; valency: 1, 3, 5, or 7; relative density: 4.93; melting pt: 113.5°C; boiling pt: 184.35°C

Word Origin for iodine

C19: from French iode, from Greek iōdēs rust-coloured, but taken to mean violet-coloured, through a mistaken derivation from ion violet

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for iodine

iodine

1814, formed by English chemist Sir Humphrey Davy (1778-1829) from French iode "iodine," coined 1812 by French chemist Joseph Louis Gay-Lussac from Greek ioeides "violet-colored," from ion "the violet; dark blue flower," + eidos "appearance" (see -oid). Davy added the chemical suffix -ine (2) to make it analogous with chlorine and fluorine. So called from the color of the vapor given off when the crystals are heated.

Medicine definitions for iodine

iodine

[ ī′ə-dīn′, -dĭn, -dēn′ ]

n.

A poisonous halogen element having compounds used as germicides, antiseptics, and food supplements, with numerous radioactive isotopes, which are used in diagnosis and treatment of thyroid diseases and neuroendocrine tumors. Atomic number 53.

A liquid containing iodine dissolved in ethyl alcohol, used as an antiseptic for wounds.

Science definitions for iodine

iodine

[ ī′ə-dīn′ ]

I

A shiny, grayish-black element of the halogen group. It is corrosive and poisonous and occurs in very small amounts in nature except for seaweed, in which it is abundant. Iodine compounds are used in medicine, antiseptics, and dyes. Atomic number 53; atomic weight 126.9045; melting point 113.5°C; boiling point 184.35°C; specific gravity (solid, at 20°C) 4.93; valence 1, 3, 5, 7. See Periodic Table.