interaction

noun

in·​ter·​ac·​tion ˌin-tər-ˈak-shən 

: mutual or reciprocal action or influence

interactional

ˌin-tər-ˈak-sh(ə-)nəl 

adjective

Synonyms of interaction

• relation
• intercourse
• dealings

Examples of interaction in a Sentence

she guessed from the friendly interaction that they were close to the other parents in the organization

Recent Examples on the Web

At the nanoscale, properties can shift dramatically because quantum effects and the forces acting at a material’s surface — such as electrostatic and other molecular interactions — begin to dominate their behavior. — Prabhat Ranjan Mishra, Interesting Engineering, 10 Sep. 2026

Feedback and interaction in the comments will always be welcomed. — Saad Yousuf, New York Times, 9 Sep. 2026

Eventually, by the time the story reaches the 1950s, and Landau is visited by a friend released from prison, that same atmosphere follows him home, in the form of minor interactions tinged with an air of paranoia. — Siddhant Adlakha, IndieWire, 9 Sep. 2026

Indeed, this fate may not have been sealed yet; interactions with the surrounding gas could determine what shape this system takes in the future. — Robert Lea, Space.com, 9 Sep. 2026

Word History

First Known Use

1832, in the meaning defined above

Rhymes for interaction

• benefaction
• counteraction
• liquefaction
• putrefaction
• rarefaction
• satisfaction
• stupefaction
• tumefaction
• abstraction
• attraction
• compaction
• contraction

Kids Definition

interaction

noun

in·​ter·​ac·​tion ˌint-ə-ˈrak-shən 

: the action or influence of people, groups, or things on one another

interactional

-shnəl 

-shən-ᵊl

adjective

Medical Definition

interaction

noun

in·​ter·​ac·​tion ˌint-ə-ˈrak-shən 

: mutual or reciprocal action or influence

interaction of the heart and lungs

interactional

-shnəl, -shən-ᵊl 

adjective