interaction
n. C / Un. the process of two or more people or things communicating with or reacting to each other. You use this when people talk to each other or when two chemicals have an effect on one another.
n. the process by which two or more entities have a reciprocal effect or influence on one another. Often used to describe social communication or the physical relationship between variables.
The interaction between the two students is very friendly.
Online learning platforms often lack the face-to-face interaction that helps students stay motivated during difficult lessons.
The study examines the complex interaction between genetic predispositions and environmental factors in determining long-term health outcomes for urban populations.
Borrowed from Medieval Latin interāctiō.
Often takes the preposition 'between' or 'with'. When used as an uncountable noun, it refers to the general concept of communicating; as a countable noun, it refers to a specific instance of contact.