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

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

Your reaction to something that has happened or something that you have experienced is what you feel, say, or do because of it.

Usage: Reaction is used to refer both to an instant response (her reaction was one of amazement) and to a considered response in the form of a statement (the Minister gave his …

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.

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 …

Dec 14, 2025 · reaction (plural reactions) An action or statement in response to a stimulus or other event.

Look up reaction in Wiktionary, the free dictionary. Reaction may refer to a process or to a response to an action, event, or exposure.

The meaning of REACT is to exert a reciprocal or counteracting force or influence —often used with on or upon. How to use react in a sentence.

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