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ion

[ahy-uh n, ahy-on] /ˈaɪ ən, ˈaɪ ɒn/
noun, Physics, Chemistry
1.
an electrically charged atom or group of atoms formed by the loss or gain of one or more electrons, as a cation (positive ion) which is created by electron loss and is attracted to the cathode in electrolysis, or as an anion (negative ion) which is created by an electron gain and is attracted to the anode. The valence of an ion is equal to the number of electrons lost or gained and is indicated by a plus sign for cations and a minus sign for anions, thus: Na + , Cl−, Ca ++ , S = .
2.
one of the electrically charged particles formed in a gas by electric discharge or the like.
Origin
< Greek ión going, neuter present participle of iénai to go; term introduced by Michael Faraday in 1834

Ion

[ahy-on] /ˈaɪ ɒn/
noun
1.
Classical Mythology. the eponymous ancestor of the Ionians: a son of Apollo and Creusa who is abandoned by his mother but returns to become an attendant in Apollo's temple at Delphi.
2.
(italics) a drama on this subject (415? b.c.) by Euripides.
Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2014.
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Examples for ions
  • The ionosphere is named for the ions created within this layer by energetic particles from sunlight and outer space.
  • Acids react with carbonate ions, in effect tying them up.
  • The smashup also creates charged atoms, or ions, that are detectable.
  • Hydrogen peroxide reduces other chemicals into iodide ions.
  • It is plasma--an electrically charged, high-energy soup of ions and electrons.
  • Up till this point, nestled in between casein molecules have been calcium ions, which help hold the proteins together.
  • These charged atoms or molecules are known as ions, and the amount of charge on an ion is known as its oxidation state.
  • These quantum particles could be ions, atoms, or subatomic particles.
  • When the protein sees the light, it opens up and allows ions to enter the neuron, making it fire.
  • When light hits the transplanted proteins, they allow ions to stream into the neurons, which makes them fire.
British Dictionary definitions for ions

ion

/ˈaɪən; -ɒn/
noun
1.
an electrically charged atom or group of atoms formed by the loss or gain of one or more electrons See also cation, anion
Word Origin
C19: from Greek, literally: going, from ienai to go
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
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Word Origin and History for ions
ion
1834, introduced by Eng. physicist and chemist Michael Faraday (suggested by the Rev. William Whewell, Eng. polymath), coined from Gk. ion, neut. prp. of ienai "go," from PIE base *ei- "to go, to walk" (cf. Gk. eimi "I go;" L. ire "to go," iter "a way;" O.Ir. ethaim "I go;" Ir. bothar "a road" (from *bou-itro- "cows' way"), Gaulish eimu "we go," Goth. iddja "went," Skt. e'ti "goes," imas "we go," ayanam "a going, way;" Avestan ae'iti "goes;" O.Pers. aitiy "goes;" Lith. eiti "to go;" O.C.S. iti "go;" Bulgarian ida "I go;" Rus. idti "to go"). So called because ions move toward the electrode of opposite charge. Ionosphere coined 1926 by R.A. Watson-Watt.
Online Etymology Dictionary, © 2010 Douglas Harper
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ions in Medicine

ion i·on (ī'ən, ī'ŏn')
n.
An atom or a group of atoms that has acquired a net electric charge by gaining or losing one or more electrons.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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ions in Science
ion
  (ī'ən, ī'ŏn')   
An atom or a group of atoms that has an electric charge. Positive ions, or cations, are formed by the loss of electrons; negative ions, or anions, are formed by the gain of electrons.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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ions in Culture
ion [(eye-uhn, eye-on)]

An atom that has either lost or gained one or more electrons, so that it has an electrical charge. Ions can be either positively or negatively charged.

The American Heritage® New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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Related Abbreviations for ions

ION

Institute of Nutrition
The American Heritage® Abbreviations Dictionary, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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