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

Click anywhere to start. This is a simple tool to measure your reaction time. The average (median) reaction time is 273 milliseconds, according to the data collected so far. In addition to measuring …

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 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.

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

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 …

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