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.

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.

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 …

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

Explore what makes a reaction happen by colliding atoms and molecules. Design experiments with different reactions, concentrations, and temperatures. When are reactions reversible? …

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.

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. …

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