Definition of "react" in English

verb

1. (intransitive) To act in response.

   • How did she react to the news?

2. (transitive, now rare) To act or perform a second time; to do over again; to reenact.

3. (physics, intransitive) To return an impulse or impression; to resist the action of another body by an opposite force

   • Every body reacts on the body that impels it from its natural state.

4. (chemistry, intransitive) To act upon each other; to exercise a reciprocal or a reverse effect, as two or more chemical agents; to act in opposition.

5. (chemistry, transitive) To cause chemical agents to react; to cause one chemical agent to react with another.

6. (Internet, intransitive) To post a reaction (icon or emoji indicating how one feels about a posted message).

noun

1. (Internet) An emoji used to express a reaction to a post on social media.

   • Sad reacts only