noun Physics, Chemistry.
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=.
one of the electrically charged particles formed in a gas by electric discharge or the like.
Origin of ion
< Greek ión going, neuter present participle of iénai to go; term introduced by Michael Faraday in 1834
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
British Dictionary definitions for negative ion
an electrically charged atom or group of atoms formed by the loss or gain of one or more electronsSee also cation, anion
Word Origin for ion
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
Word Origin and History for negative ion
1834, introduced by English physicist and chemist Michael Faraday (suggested by the Rev. William Whewell, English polymath), coined from Greek ion, neuter present participle of ienai "go," from PIE root *ei- "to go, to walk" (cf. Greek eimi "I go;" Latin ire "to go," iter "a way;" Old Irish ethaim "I go;" Irish bothar "a road" (from *bou-itro- "cows' way"), Gaulish eimu "we go," Gothic iddja "went," Sanskrit e'ti "goes," imas "we go," ayanam "a going, way;" Avestan ae'iti "goes;" Old Persian aitiy "goes;" Lithuanian eiti "to go;" Old Church Slavonic iti "go;" Bulgarian ida "I go;" Russian idti "to go"). So called because ions move toward the electrode of opposite charge.
Online Etymology Dictionary, © 2010 Douglas Harper
Medicine definitions for negative ion
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.
Science definitions for negative ion
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.
Culture definitions for negative ion
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.