Ion

How to spell ion

3 letters · 2 syllables

How to pronounce ion

Say the part in capitals loudest.

What does ion mean?

1. nounAn atom or molecule that carries a net electric charge because it has gained or lost one or more electrons.

Ion in a sentence

• A sodium ion forms when the atom loses a single electron.

• The battery works by moving each charged ion between the electrodes.

Where does ion come from?

Language of origin: Greek

This word comes directly from the Greek ion, meaning 'going' or 'that which goes', the neuter present participle of the verb ienai, 'to go'. It was coined in 1834 by the English scientist Michael Faraday, on the suggestion of the polymath William Whewell, to name the electrically charged particles that travel through a solution toward the electrodes during electrolysis. The choice of a word meaning 'going' was deliberate and rather elegant, since these particles literally move: those drawn to the positive anode were called anions and those drawn to the negative cathode were called cations. The same Greek root for movement also lies behind words like 'exit', through the related Latin family of going and leaving. Because the spelling simply mirrors its short sound, the only real trap is remembering it is a true three-letter word with no silent or doubled letters.

How the word is built

• ion (from Greek ion, 'going'; the neuter present participle of ienai 'to go')