Cambridge Dictionaries online Cambridge Dictionaries online

The most popular online dictionary and thesaurus for learners of English

English definition of “ion”

See all translations

ion

noun [C] /ˈaɪ.ən/ specialized us  
an atom or small group of atoms that has an electrical charge because it has added or lost one or more electrons
ionic
adjective uk   /aɪˈɒn.ɪk/ us    /-ˈɑː.nɪk/
ionic bonding
Translations of “ion”
in Spanish ión, ion…
in Chinese (Traditional) 離子…
in Chinese (Simplified) 离子…
(Definition of ion noun from the Cambridge Advanced Learners Dictionary & Thesaurus © Cambridge University Press)
What is the pronunciation of ion?
Add Cambridge dictionaries to your browser to your website

Definitions of “ion” in other dictionaries

Word of the Day

white Christmas

a Christmas when it snows

Word of the Day

Cleavage proves divisive in Cambridge’s words of 2014

by Alastair Horne,
December 19, 2014
​​​​ Other dictionaries may choose faddish novelties as their words of the year, but here at Cambridge, we like to do something different. We look for the words that have seen sudden surges in searches over the course of the year – words that have been baffling users of English and driven them

Read More 

cinderella surgery noun

December 15, 2014
cosmetic surgery to the feet We have all heard of people having nose jobs, boob jobs and liposuction – but now a new trend growing in popularity in America: Cinderella surgery.

Read More