[ in-ter-ak-shuhn ]
See synonyms for: interactioninteractions on

  1. reciprocal action, effect, or influence.

  2. Physics.

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

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

Origin of interaction

First recorded in 1825–35; inter- + action

Other words from interaction

  • in·ter·ac·tion·al, adjective Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use interaction in a sentence

British Dictionary definitions for interaction


/ (ˌɪntərˈækʃən) /

  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

Derived forms of interaction

  • interactional, adjective

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012