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.

Chemical reactions are caused by electrons of one substance interacting with those of another. The reaction of an acid with a base, for example, results in the creation of a salt and water. …

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.

Dec 4, 2025 · reaction (plural reactions) An action or statement in response to a stimulus or other event.

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 …

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 reaction to the court's …

Reaction definition: A reverse or opposing action.

reaction noun (CHANGE) a change in the way people behave or think because they do not agree with the way people behaved or thought in the past: