ion

[ ahy-uhn, ahy-on ]

nounPhysics, 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 of ion

1
<Greek ión going, neuter present participle of iénai to go; term introduced by Michael Faraday in 1834

Other definitions for Ion (2 of 4)

Ion
[ ahy-on ]

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.

Other definitions for -ion (3 of 4)

-ion

  1. a suffix, appearing in words of Latin origin, denoting action or condition, used in Latin and in English to form nouns from stems of Latin adjectives (communion; union), verbs (legion; opinion), and especially past participles (allusion; creation; fusion; notion; torsion).

Origin of -ion

3
<Latin -iōn- (stem of -iō) suffix forming nouns, especially on past participle stems; replacing Middle English -ioun<Anglo-French <Latin -iōn-

Other definitions for Ion. (4 of 4)

Ion.

abbreviation
  1. Ionic.

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2024

How to use ion in a sentence

British Dictionary definitions for ion (1 of 2)

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

Origin of ion

1
C19: from Greek, literally: going, from ienai to go

British Dictionary definitions for -ion (2 of 2)

-ion

suffix forming nouns
  1. indicating an action, process, or state: creation; objection Compare -ation, -tion

Origin of -ion

2
from Latin -iōn-, -io

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

Scientific definitions for ion

ion

[ īən, īŏn′ ]


  1. 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 © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Cultural definitions for ion

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 New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.