Definition of react
1 : to exert a reciprocal or counteracting force or influence —often used with on or upon
2 : to change in response to a stimulus
3 : to act in opposition to a force or influence —usually used with against
4 : to move or tend in a reverse direction
5 : to undergo chemical reaction
: to cause to react
Examples of react in a Sentence
When I told her what happened, she reacted with anger.
I didn't expect him to react that way.
The firefighters reacted quickly when they heard the alarm.
He reacted badly to the drug.
Recent Examples of react from the Web
Smith took time during his football camp at Shawnee Mission West on Saturday to react to address his friend’s departure.
Inside the hospital, Orlando police officers reacted immediately, searching for a potential threat.
The United Nations had been woefully slow to react to the crisis.
Some have reacted by raising rents or increasing the credit-score requirements for applicants.
Bloomberg's Manus Cranny reports on how market leaders are reacting to OPEC and non-OPEC producers agreeing to a nine-month extension of supply cuts.
Before a company knew what hit it, Wall Street could react on a suspicion that something was amiss.
Reacting to the explosion in memes, Mr. Temer’s government moved this week to stop Brazilians from using official photos of the president — which are found on government websites — for such purposes.
A chemical micromotor would use a catalyst like platinum or silver within the motor to react with the liquids surrounding it.
These example sentences are selected automatically from various online news sources to reflect current usage of the word 'react'. Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.
Origin and Etymology of react
New Latin reactus, past participle of reagere, from Latin re- + agere to act — more at agent
First Known Use: 1644
REACT Defined for English Language Learners
Definition of react for English Language Learners
: to behave or change in a particular way when something happens, is said, etc.
of a chemical substance : to change after coming into contact with another substance
medical : to be affected by a drug, food, etc., in usually a bad way
REACT Defined for Kids
Definition of react for Students
1 : to act or behave in response to something Firefighters reacted quickly to the situation.
2 : to oppose a force or influence Hint: In this sense, react is usually used with against. Workers reacted against unfair treatment.
3 : to go through a chemical reaction Acids react with bases to form salt.
Seen and Heard
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