'互动' (hù dòng) literally combines '互' (hù), meaning 'mutual' or 'each other', and '动' (dòng), meaning 'to move' or 'to act'. Together, they express the idea of reciprocal action — two or more parties actively engaging with and responding to one another. It emphasizes two-way communication or exchange, not just one-sided activity.

This word is widely used in education, technology, media, and daily life to describe situations where participants influence each other — such as classroom discussions, touchscreen interfaces, live-stream chats, or group games. As a noun, it refers to the interaction itself ('a lively interaction'); as an adjective, it modifies nouns to indicate interactivity ('interactive learning'). Unlike passive observation, 互动 always implies active, responsive participation from all sides.