re·​act | \ rē-ˈakt How to pronounce react (audio) \
reacted; reacting; reacts

Definition of react

intransitive verb

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

transitive verb

: to cause to react

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Synonyms for react


reply, respond

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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.
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Recent Examples on the Web

The most obvious steps are to react in the moment, challenging a comment, for example. Liz Reyer, The Seattle Times, "How to take on someone who says sexist and demeaning things at work," 25 Mar. 2019 Warren has not been particularly fast to react to questions about her heritage. Emily Stewart, Vox, "Elizabeth Warren releases her DNA test results and dares Trump to make good on his $1 million bet," 15 Oct. 2018 Of course, fans of the two have been reacting to the post on social media. Nicole Weaver, Teen Vogue, "Kiernan Shipka Proposed to Noah Centineo on Instagram," 11 Sep. 2018 Tottenham fans have been reacting online to Toby Alderweireld's recent tweet about fellow Belgian striker Romelu Lukaku., "Tottenham Fans Frustrated With Star Man's Tweet About Romelu Lukaku After Belgium Brace," 24 June 2018 The South had been reacting to a North Korean nuclear test. Washington Post, "Koreas agree to restore military communication lines," 14 June 2018 Both ideas, though different, react towards one common problem in the fashion industry: plastic. Teen Vogue, "Kick Off Earth Day With These 6 Sustainable Sneakers," 22 Apr. 2019 How will George, Charlotte, and Louis react to their new cousin?? Katherine J. Igoe, Marie Claire, "Why Prince William May Miss Meghan Markle and Harry's Baby's Birth," 31 Mar. 2019 Chelsea's Eden Hazard reacts after Manchester City's Sergio Aguero scores to complete a hat-trick. Joshua Robinson, WSJ, "Chelsea May Have to Hit the Reset Button, Again," 22 Feb. 2019

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.

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First Known Use of react

1644, in the meaning defined at intransitive sense 1

History and Etymology for react

New Latin reactus, past participle of reagere, from Latin re- + agere to act — more at agent

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Statistics for react

Last Updated

13 May 2019

Look-up Popularity

Time Traveler for react

The first known use of react was in 1644

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More Definitions for react



English Language Learners Definition of react

: 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


re·​act | \ rē-ˈakt How to pronounce react (audio) \
reacted; reacting

Kids Definition of react

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.
re·​act | \ rē-ˈakt How to pronounce react (audio) \

Medical Definition of react

1 : to respond to a stimulus
2 : to undergo chemical reaction

transitive verb

: to cause to react

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More from Merriam-Webster on react

Rhyming Dictionary: Words that rhyme with react

Thesaurus: All synonyms and antonyms for react

Spanish Central: Translation of react

Nglish: Translation of react for Spanish Speakers

Britannica English: Translation of react for Arabic Speakers

Comments on react

What made you want to look up react? Please tell us where you read or heard it (including the quote, if possible).


using a distributed computer network

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