1
: an atom or group of atoms that carries a positive or negative electric charge as a result of having lost or gained one or more electrons
2
: a charged subatomic particle (such as a free electron)

Ion

2 of 3

abbreviation

Ionic

-ion

3 of 3

noun suffix

1
a
: act or process
validation
b
: result of an act or process
regulation
2
: state or condition
hydration

Examples of ion in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Noun
Solid-state batteries still use lithium as the primary ion donor, the actual upgrade is replacing the traditional 'liquid' or 'gel' electrolyte with a 'solid electrolyte. New Atlas, 15 June 2026 These waters—rich in chloride, hydrogen sulfide, iron, fluoride, and iodide ions—promote blood circulation and muscle relaxation, boost metabolism, strengthen the immune system, and lower stress and inflammation. Devorah Lev-Tov, Travel + Leisure, 13 June 2026 Under the novel agreement, General Motors will design and develop the sodium-ion cells at its battery laboratories in the state of Michigan. Georgina Jedikovska, Interesting Engineering, 11 June 2026 Peak Energy already has sodium-ion NFPP ESS deployed. Roberto Baldwin, ArsTechnica, 10 June 2026 See All Example Sentences for ion

Word History

Etymology

Noun

Greek, neuter of iōn, present participle of ienai to go — more at issue entry 1

Noun suffix

French -ion, from Latin -ion-, -io

First Known Use

Noun

circa 1834, in the meaning defined at sense 1

Time Traveler
The first known use of ion was circa 1834

Browse Nearby Words

Cite this Entry

“Ion.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/ion. Accessed 19 Jun. 2026.

Kids Definition

ion

1 of 2 noun
ˈī-ən How to pronounce ion (audio)
ˈī-ˌän
: an atom or group of atoms that carries a positive or negative electric charge as a result of having lost or gained one or more electrons

-ion

2 of 2 noun suffix
1
a
: act or process
validation
b
: result of an act or process
regulation
2
: state or condition
hydration
Etymology

Noun suffix

derived from Latin -ion (suffix) "act or process"

Medical Definition

1
: an atom or group of atoms that carries a positive or negative electric charge as a result of having lost or gained one or more electrons see anion, cation
2
: a charged subatomic particle (as a free electron)

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