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
General Motors is backing a sodium-ion battery push aimed at making electricity storage cheaper for utilities and data centers. — Atharva Gosavi, Interesting Engineering, 24 Oct. 2026 Our model estimated that the living Black and white populat,ion representing about 217 million people, had 755 million ties to deceased close relatives. — Ashton Verdery, The Conversation, 23 Oct. 2026 The company’s latest hardware, called Helios, rotates the ions around a ring, selectively shifting the appropriate ones into one of two arms where measurements and operations of the ions’ quantum states can be performed using lasers. — ArsTechnica, 20 Oct. 2026 By his reckoning, lithium-ion technology is at best 20% of the way through its maturity curve, maybe 10% by conservative estimates. — Nick Lichtenberg, Fortune, 15 Oct. 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

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Cite this Entry

“Ion.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/ion. Accessed 25 Oct. 2026.

Kids Definition

ion

1 of 2 noun
: 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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