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

After an interaction with Nye in July 2024, Kamra gave evidence that he was "dissatisfied" and that questions he had for Nye were still not answered.

From BBC ● Sep. 18, 2026

Maintaining an openness to people — and a willingness to strengthen connections with everyone from distant or estranged family members to friends, acquaintances and strangers — enables you to benefit from more social interaction.

From MarketWatch ● Sep. 18, 2026

Some teams work in person, collaborating face-to-face in a single room to make interaction easier and more spontaneous.

From The Wall Street Journal ● Sep. 17, 2026

But one thing was very clear at the inquest – there was no evidence of any physical interaction between Noah and anyone else during his final bicycle ride from his home to north Belfast.

From BBC ● Sep. 15, 2026

It is necessary to take into account the interaction of ideas, images and fantasies as well.

From "Sapiens: A Brief History of Humankind" by Yuval Noah Harari

“It certainly would raise questions, you know, in my mind about what sort of interactions he, on behalf of Damen, had with the U.S. government,” Rosenstein said.

From Salon ● Sep. 16, 2026

"These are only very few of the interactions I've been lucky enough to have that remind me how profoundly Catherine has impacted the world, and it's because she brought us joy," Murphy said.

From BBC ● Sep. 15, 2026

The limited research available offers some indications that children and adults process AI interactions differently.

From Los Angeles Times ● Sep. 14, 2026

"There is way more overlap than you would expect just by random chance between the genes that are associated with longevity and genes that are associated with viral interactions," he said.

From Science Daily ● Sep. 12, 2026

In my regular interactions at work or around town, I’d find myself casually uttering this strange new term—“my husband.”

From "Becoming" by Michelle Obama

Related Words

• communication
• cooperation
• synergy