• synonyms


verb (used with object), i·on·ized, i·on·iz·ing.
  1. to separate or change into ions.
  2. to produce ions in.
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verb (used without object), i·on·ized, i·on·iz·ing.
  1. to become changed into the form of ions, as by dissolving.
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Also especially British, i·on·ise.

Origin of ionize

First recorded in 1895–1900; ion + -ize
Related formsi·on·iz·a·ble, adjectivei·on·i·za·tion, nouni·on·iz·er, nounnon·i·on·ized, adjectivenon·i·on·iz·ing, adjectiveself-i·on·i·za·tion, nounun·i·o·nized, adjectiveun·un·ion·ized, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for ionised

Historical Examples of ionised

  • Such electrified atoms are absent from the sugar solution: sugar does not become "ionised" when it is dissolved.

    The Birth-Time of the World and Other Scientific Essays

    J. (John) Joly

British Dictionary definitions for ionised



  1. to change or become changed into ions
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Derived Formsionizable or 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

Word Origin and History for ionised



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

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Online Etymology Dictionary, © 2010 Douglas Harper

ionised in Medicine


  1. To dissociate atoms or molecules into electrically charged atoms or radicals.
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Related formsion•iz′er n.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

ionised 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.
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The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.