or kat·i·on

[ kat-ahy-uhn, -on ]
/ ˈkætˌaɪ ən, -ɒn /
Save This Word!

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).



Apostrophes can be tricky; prove you know the difference between it’s and its in this crafty quiz!
Question 1 of 12
On the farm, the feed for chicks is significantly different from the roosters’; ______ not even comparable.

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
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2021

British Dictionary definitions for cation

/ (ˈkætaɪən) /


a positively charged ion; an ion that is attracted to the cathode during electrolysisCompare anion
cationic (ˌkætaɪˈɒnɪk), adjective
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.
What's This Word?