From the ending of anion and cation, which in turn is from Ancient Greek ἰόν (ión, “going”), neuter present participle of εἶμι (eîmi, “I go”). Coined by English polymath William Whewell in 1834 for Michael Faraday, who introduced it later that year.
ion (plural ions)
- An atom or group of atoms bearing an electrical charge, such as the sodium and chlorine atoms in a salt solution.
From a corruption of I don't.