Meaning of ION in English

n. an atom or group of atoms that has lost one or more electrons ( CATION), or gained one or more electrons ( ANION).

Phrases and idioms:

ion exchange the exchange of ions of the same charge between a usu. aqueous solution and a solid, used in water-softening etc. ion exchanger a substance or equipment for this process.

Etymology: Gk, neut. pres. part. of eimi go

Oxford English vocab.      Оксфордский английский словарь.