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).

Nearby words

  1. catholicus,
  2. cathouse,
  3. cathy,
  4. catilinarian,
  5. catiline,
  6. cation exchange,
  7. cation-exchange resin,
  8. cationic,
  9. cationic detergent,
  10. catkin

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

Related formscat·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. 2019

Examples 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 Formscationic (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

Word Origin and History for cation



1834, from Greek kation "going down," neuter present participle of katienai "to go down," from kata "down" (see cata-) + ienai "to go" (see ion). Proposed by the Rev. William Whewell (1794-1866), English polymath, and published by English physicist Michael Faraday.

Online Etymology Dictionary, © 2010 Douglas Harper

Medicine 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.

Science 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.