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

The project also included heavy-ion radiation testing conducted by NASA to evaluate the platform’s resilience for orbital and lunar missions. — Neetika Walter, Interesting Engineering, 30 June 2026

Analyst Jack Lu and his team at the bank predict sodium-ion batteries will account for 20% of total battery deployment market share by 2030 and 37% in 2035. — Alex Harring, CNBC, 28 June 2026

The researchers used specific emissions from hydrogen and calcium ions as a marker for activity in the chromosphere. — John Timmer, ArsTechnica, 25 June 2026

Another lithium-ion fire in 2024 forced authorities to close one of the major freeways leading out of the Port of Los Angeles and Long Beach for a day. — Tom Wait, CBS News, 24 June 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)