Meaning & Definition of Reaction in English

1. (chemistry) a process in which one or more substances are changed into others

• "There was a chemical reaction of the lime with the ground water"

2. An idea evoked by some experience

• "His reaction to the news was to start planning what to do"

3. A bodily process occurring due to the effect of some antecedent stimulus or agent

• "A bad reaction to the medicine"

• "His responses have slowed with age"

4. (mechanics) the equal and opposite force that is produced when any force is applied to a body

• "Every action has an equal and opposite reaction"

5. A response that reveals a person's feelings or attitude

• "He was pleased by the audience's reaction to his performance"

• "John feared his mother's reaction when she saw the broken lamp"

6. Extreme conservatism in political or social matters

• "The forces of reaction carried the election"

7. Doing something in opposition to another way of doing it that you don't like

• "His style of painting was a reaction against cubism"