The meaning of REACTION is the act or process or an instance of reacting. How to use reaction in a sentence.

A reaction is an action taken in response to something. If you're telling your parents that you want to move out, you'll see by their reaction that they're sad about it.

A reaction can also be an unpleasant effect on the body resulting from something eaten or taken, such as a drug.

Your reaction to something that has happened or something that you have experienced is what you feel, say, or do because of it. Reaction to the visit is mixed. A reaction against something is a way of …

Reaction may refer to a process or to a response to an action, event, or exposure.

Jan 20, 2026 · Noun reaction (plural reactions) An action or statement in response to a stimulus or other event.

For sense development, see reaction. The word meaning "perform again, do a second time" (often written re-act and given full pronunciation of the prefix to distinguish it from react) is attested from …

REACTION definition: a reverse movement or tendency; an action in a reverse direction or manner. See examples of reaction used in a sentence.

Definition of reaction noun in Oxford Advanced Learner's Dictionary. Meaning, pronunciation, picture, example sentences, grammar, usage notes, synonyms and more.

REACTION meaning: 1 : the way someone acts or feels in response to something that happens, is said, etc.; 2 : an action or attitude that shows disagreement with or disapproval of someone or something …