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

A chemical reaction is the change that happens when two or more substances are mixed with each other.

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

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 …

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.

Find 78 different ways to say REACTION, along with antonyms, related words, and example sentences at Thesaurus.com.

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

reaction meaning, definition, what is reaction: something that you feel or do because of...: Learn more.

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.