Definition of ion in English:

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Pronunciation: /ˈīən/
Pronunciation: /ˈīˌän/


An atom or molecule with a net electric charge due to the loss or gain of one or more electrons. See also cation, anion.
Example sentences
  • Some compounds have polyatomic ions, where the ion is composed of two or more atoms.
  • The charge on the complex ion is the sum of the charges on the metal ion and the ligands.
  • At that stage, the electrons and ions combined into neutral atoms that no longer scattered the radiation.


Mid 19th century: from Greek, neuter present participle of ienai 'go'.

Words that rhyme with ion

Brian, cyan, Gaian, Geminian, Hawaiian, iron, Ixion, lion, Lyon, Mayan, Narayan, O'Brien, Orion, Paraguayan, prion, Ryan, scion, Uruguayan, Zion

For editors and proofreaders

Syllabification: i·on

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