ion

1 of 3

noun

ˈī-ən  ˈī-ˌän 

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

Noun

Water always contains a small number of hydroxide ions, and turning one into a hydroxyl radical requires stripping away an electron. — Jacek Krywko, ArsTechnica, 15 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

Fluorine is then released into the water as fluoride ions, while hydroxyl radicals and hydroxide ions help sever carbon-carbon bonds in the remaining molecular chains. — Alexandra Harrell, Footwear News, 14 Oct. 2026

The Zero holds six 18650 lithium-ion cells of 3,500 mAh each, which works out to about 21,000 mAh. — New Atlas, 14 Oct. 2026

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

Phrases Containing ion

• hydrogen ion
• ion channel
• ion engine
• ion exchange
• ion exchange resin
• lithium-ion battery

Rhymes for ion

• amphitryon
• dandelion
• herodian
• hawaiian
• ixion
• mauryan
• orion
• procyon
• visayan
• heian
• lion
• mayan

Kids Definition

ion

1 of 2 noun

ˈī-ən 

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

ion

noun

ˈī-ən  ˈī-ˌän 

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)