reaction
UK: riˈækʃən | US: riˈækʃən
n. 1. A response to a stimulus or event.
n. 2. A chemical process where substances interact to form new compounds.
n. 3. An opposing force or resistance to change.
The word "reaction" originates from Latin reactionem (a returning, opposition), derived from reagere ("to act in return"). The prefix re- (again/back) combines with agere (to do, act), reflecting the idea of "acting in response." Over time, it evolved in Middle French as réaction before entering English, broadening to encompass scientific and general responses.
Her immediate reaction to the news was shock.
The chemical reaction produced a bright flame.
The market showed a negative reaction to the policy change.
His speech triggered a strong reaction from the audience.
Newton’s third law states that every action has an equal and opposite reaction.