Definitions

1. noun

A natural or normal response to a stimulus; an emotional or instinctive response to a situation or event.

“She had a strong reaction to the bad news and broke down in tears.”

2. noun

A chemical change in a substance resulting from a reaction with another substance; a chemical process involving the transformation of one substance into another.

“The reaction between the acid and base produced a lot of heat and smoke.”

3. noun

A response or reply to something, especially a statement or an action.

“Her reaction to the joke was immediate and loud laughter.”

4. verb

To respond or answer something, especially a question or a stimulus.

“He reacted quickly to the emergency and helped the injured person.”

5. verb

To cause a chemical change or transformation in a substance.

“The catalyst reacted with the chemicals to produce a new compound.”