or kat·i·on

[ kat-ahy-uh n, -on ]
/ ˈkætˌaɪ ən, -ɒn /

noun Physical Chemistry.

a positively charged ion that is attracted to the cathode in electrolysis.
any positively charged atom or group of atoms (opposed to anion).


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Origin of cation

1825–35; < Greek katión going down (neuter of katiṓn, present participle of kateînai), equivalent to kat- cat- + -i- go + -on neuter present participle suffix


cat·i·on·ic [kat-ahy-on-ik] /ˌkæt aɪˈɒn ɪk/, adjectivecat·i·on·i·cal·ly, adverb Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020

Example sentences from the Web for cation

British Dictionary definitions for cation

/ (ˈkætaɪən) /


a positively charged ion; an ion that is attracted to the cathode during electrolysisCompare anion

Derived forms of cation

cationic (ˌkætaɪˈɒnɪk), adjective

Word Origin for cation

C19: from cata- + ion
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

Medical definitions for cation

[ kătī′ən ]


An ion or group of ions having a positive charge and characteristically moving toward the negative electrode in electrolysis.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

Scientific definitions for cation

[ kătī′ən ]

An ion with net positive charge, having more protons than electrons. In electrolysis, cations migrate to a negatively charged cathode. Compare anion.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.