interaction

American  

[in-ter-ak-shuhn] / ˌɪn tərˈæk ʃən /

noun

• interactions
  plural

1. reciprocal action, effect, or influence.

2. Physics.

   1. the direct effect that one kind of particle has on another, in particular, in inducing the emission or absorption of one particle by another.

   2. the mathematical expression that specifies the nature and strength of this effect.

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interaction British  

/ ˌɪntərˈækʃən /

noun

1. a mutual or reciprocal action or influence

2. physics the transfer of energy between elementary particles, between a particle and a field, or between fields See strong interaction electromagnetic interaction fundamental interaction gravitational interaction weak interaction electroweak interaction

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Other Word Forms

Derived Forms

• interactional
  adjective

Inflected Forms

Nouns

• interactions
  plural

Etymology

Origin of interaction

First recorded in 1825–35; inter- + action

Explanation

If you interact with someone — by talking, looking, sharing, or engaging in any kind of action that involves the two of you — you can be said to have had an interaction with that person. Interaction comes from Latin inter meaning "between," and ago meaning "to do" or "to act" — any “action between” is considered an interaction, like the interaction between a teacher and a student, two countries, or even baking soda and vinegar (boom!).

Example Sentences

See Examples For:

interaction interactions

Under these conditions, the interaction between light and sound becomes more than 1000 times stronger than it is in standard optical fibers.

From Science Daily ● Aug. 22, 2026

The iPhone is also a sort of “consumer AI ‘toll booth,’” he said, given its role as “the primary AI interaction device” for users.

From MarketWatch ● Aug. 21, 2026

This is, of course, exactly the sort of interaction that restaurant apps are forever attempting to imitate.

From Salon ● Aug. 20, 2026

In July this year, UBTech drew global attention when it unveiled what Chinese state media described as a "hyper-realistic" robots designed to offer "emotional support and everyday interaction."

From BBC ● Aug. 19, 2026

He hated any interaction with the police, but now he was inviting them into his life in a way that seemed absurd.

From "Anger Is a Gift" by Mark Oshiro

But he is cheered by the interactions because, whether fans love him as a good guy, a bad guy or a character in between, they all want the same thing.

From Los Angeles Times ● Aug. 18, 2026

When chatbots constantly tell people how great they are, they start to expect kudos in human interactions, too—and feel bad when they don’t get them, Turkle says.

From The Wall Street Journal ● Aug. 16, 2026

Even so, researchers are still working to understand exactly how gut bacteria process the many components of plant foods and how those interactions produce beneficial effects.

From Science Daily ● Aug. 15, 2026

"Unlike previous interactions with insurance" he got a quick reply, he said.

From BBC ● Aug. 14, 2026

Unlike Handsome, for example, who was relaxed in both musk ox and non–musk ox interactions, C.C. could never quite grasp what was expected.

From "The Very, Very Far North" by Dan Bar-el

Related Words

• communication
• cooperation
• synergy