To act in response.
To act upon each other; to exercise a reciprocal or a reverse effect, as two or more chemical agents; to act in opposition.
To post a reaction (icon or emoji indicating how one feels about a posted message).
To return an impulse or impression; to resist the action of another body by an opposite force
To cause chemical agents to react; to cause one chemical agent to react with another.
An emoji used to express a reaction to a post on social media.
To seat (someone) again, to give somebody a different seat.
To fit (something, especially a valve) back into its place.
To sit down again.
To provide (e.g. a room) with more, or new, seats.
To plug (something) back into its socket.