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

To avoid the subject material being exposed to Earth's atmosphere and reacting with its oxygen, the ion beam cored into the samples, extracting the beads from within them, and then taking care that the material was protected from our atmosphere. —Keith Cooper, Space.com, 17 June 2025

This process lowers the pH of seawater and reduces the amount of carbonate ions, which are essential building blocks for many marine creatures. —Thomas Westerholm, MSNBC Newsweek, 16 June 2025

Federal regulators grounded the entire 787 fleet worldwide for more than three months after lithium ion batteries caught fire on two of the aircraft in 2013, leading to smoldering fires in the cargo hold. —Bill Chappell, NPR, 12 June 2025

Positive ions flow in, causing a voltage change within the neuron that triggers it to fire with an action potential (3) that travels down the axon. —Sangeeta S. Chavan, IEEE Spectrum, 9 June 2025

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
• hawaiian
• ixion
• orion
• procyon
• visayan
• heian
• lion
• mayan
• scion

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)