Origin: Latin suffix -tion
Reaction has 8 different meanings across 1 category:
(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"
an idea evoked by some experience
"his reaction to the news was to start planning what to do"
(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"
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"
extreme conservatism in political or social matters
"the forces of reaction carried the election"
doing something in opposition to another way of doing it that you don't like
"his style of painting was a reaction against cubism"
An action or statement in response to a stimulus or other event.
"Her sharp reaction to the sudden noise made everyone turn around to see what had happened."
In plain English: A reaction is what happens when something changes because of another thing.
"The crowd cheered in reaction to the winning goal."
Usage: Use reaction when describing an immediate physical, chemical, or emotional response to something specific, such as a drug's effect on the body or a crowd's behavior after news breaks. Avoid confusing it with "response," which often implies a more deliberate action taken after consideration rather than an instinctive occurrence.
The word "reaction" comes from the Latin reāctiō, which combined the prefix meaning "again" with a verb meaning "to act." It traveled into English through Middle French and Old French, eventually becoming part of modern vocabulary to describe an action taken in response to something else.