interaction

American  

[in-ter-ak-shuhn] / ˌɪn tərˈæk ʃən /

noun

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

• interactional adjective

Etymology

Origin of interaction

First recorded in 1825–35; inter- + action

Example Sentences

“This morning, Dawn Staley and I spoke about our interaction after the game last Friday,” Auriemma wrote in a statement posted on X by the Huskies.

From Los Angeles Times • Apr. 8, 2026

The convicted man took the case to the Supreme Court, arguing that there had been no violence or intimidation in his interaction with the woman.

From BBC • Mar. 31, 2026

The more children seek social stimulation online, the less actual interaction they have with friends in person.

From The Wall Street Journal • Mar. 31, 2026

The interaction between plasma and gravity creates multiple paths for the pulsar's radio waves.

From Science Daily • Mar. 28, 2026

My interaction with Mandela was both quiet and profound—maybe more profound, even, for its quietness.

From "Becoming" by Michelle Obama

Related Words

• communication
• cooperation
• synergy