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

The research comes as people are living longer, with retirements that can last decades, making it important to have structure and social interaction in that stage of life.

From MarketWatch ● Oct. 6, 2026

Kremer’s sister caught the interaction that followed on video.

From Los Angeles Times ● Oct. 6, 2026

However, she praised the response of local authorities as "incredible", adding "they have been very warm, caring and efficient in any interaction so far".

From BBC ● Sep. 30, 2026

Videos of the encounter quickly spread online and on Spain’s front pages, leading the country’s foreign minister to defend the interaction as a greeting and “nothing more.”

From The Wall Street Journal ● Sep. 24, 2026

Ever since learning that Charlotte had a team going to the competition, Brooklyn had been carefully planning for this interaction.

From "City Spies" by James Ponti

“Officials are routinely subjected to highly charged interactions and, at times, verbal abuse from players and coaches,” Green said in the association’s news release.

From Los Angeles Times ● Oct. 6, 2026

According to Yorgason, those interactions may help explain why shared physical activity was associated with healthier communication and better conflict resolution.

From Science Daily ● Oct. 6, 2026

Gender-responsive policing recognizes that people of different genders can experience crime, victimization, and interactions with law enforcement differently.

From Slate ● Oct. 2, 2026

In his BBC interview, Burnham also said he was "of course" confident that his own interactions with City's owners as Greater Manchester mayor would stand up to scrutiny.

From BBC ● Oct. 1, 2026

Synchrony has even been found in the interactions of humans and apes.

From "The Tipping Point" by Malcolm Gladwell

Related Words

• communication
• cooperation
• synergy