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[ahy-uh-nahyz] /ˈaɪ əˌnaɪz/
verb (used with object), ionized, ionizing.
to separate or change into ions.
to produce ions in.
verb (used without object), ionized, ionizing.
to become changed into the form of ions, as by dissolving.
Origin of ionize
1895-1900; ion + -ize
Related forms
ionizable, adjective
ionization, noun
ionizer, noun
nonionized, adjective
nonionizing, adjective
self-ionization, noun
unionized, adjective
ununionized, adjective Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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Examples from the web for ionization
  • By determining when this transition took place, scientists can pin down the start date of the helium-ionization era.
  • And in the second place, when a current flows through gas, ionization occurs and charged particles are produced.
  • ionization is the separation of electrons from molecules.
  • ionization of the atmosphere and concomitant ozone depletion are unlikely to be important.
  • Simple low temperature friction can create ionization into charged particles.
British Dictionary definitions for ionization


  1. the formation of ions as a result of a chemical reaction, high temperature, electrical discharge, particle collisions, or radiation
  2. (as modifier): ionization temperature, ionization current


to change or become changed into ions
Derived Forms
ionizable, ionisable, adjective
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 ionization

1891; see ionize + -ation.



1896, from ion + -ize. Related: Ionized; ionizing.

Online Etymology Dictionary, © 2010 Douglas Harper
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ionization in Medicine

ionization i·on·i·za·tion (ī'ə-nĭ-zā'shən)

  1. The formation of or separation into ions by heat, electrical discharge, radiation, or chemical reaction; electrolytic dissociation.

  2. See iontophoresis.

ionize i·on·ize (ī'ə-nīz')
v. i·on·ized, i·on·iz·ing, i·on·iz·es
To dissociate atoms or molecules into electrically charged atoms or radicals.

i'on·iz'er n.
The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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ionization in Science
  1. To give an atom or group of atoms a net electric charge by adding or removing one or more electrons.

  2. To form ions in a substance. Lightning ionizes air, for example.

The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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