To act in a way that affects someone or something else, with both sides influencing each other.
From 'inter-' (between) + 'act', formed in English in the 19th century. It built on earlier uses of 'interaction' in science and philosophy.
To interact is to create a tiny feedback loop—what you do changes them, which changes you, and so on. Digital life is built on this concept: every click is an interaction that quietly trains the system and you at the same time.
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