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

Get our daily newsletter South Koreans have reacted with rancour. The Economist, "Relations between Japan and South Korea are fraying alarmingly," 18 July 2019 Investors who are counting on gigantic growth to sustain Netflix's lofty valuation (P/E prior to announcement: 129) reacted with terror, hammering its share price by 11% at the start of trading, and erasing $17 billion in market cap. Shawn Tully, Fortune, "Netflix Investors Should Focus on This Alarming Number—Not Subscriber Growth," 18 July 2019 The singer included a regal portrait of Meghan in her BRIT Awards acceptance video with Jay-Z in February, to which the royal reportedly reacted with the big eye (👀) emoji. Erica Gonzales, Harper's BAZAAR, "Meghan Markle Will Attend the Lion King Premiere, so Be Prepared for a Possible Beyoncé Meeting," 11 July 2019 Nitrites can damage cells and react with other molecules found in food to create an enhanced cancer risk. Alix Wall,, "Some much-loved American Jewish classic foods may increase risk of cancer," 10 July 2019 Business leaders, many of whom have long been critical of Lopez Obrador, reacted with dismay. Kate Linthicum,, "Mexico’s finance minister quits abruptly, sending peso tumbling," 9 July 2019 In the new Hubble image, hydrogen gas can be seen reacting with the bright light streams from new stars close by, which creates the telltale orange glow. Ashley Strickland, CNN, "Hubble spies a spiral galaxy blooming like roses 70 million light-years away," 8 July 2019 The man retaliates by slapping her as those nearby react with groans. Scott Craven, azcentral, "Disneyland fight on video stuns Toontown crowd. They wonder why security took 3 minutes to arrive," 8 July 2019 There's a little more of Hobbs' mother (played by Lori Pelenise Tuisano), too, who reacts with glee to her son's plan to stop Brixton, Idris Elba's evil villain. Jonathan M. Gitlin, Ars Technica, "New Hobbs and Shaw trailer stars a McLaren 720S and Hobbs’ mom," 28 June 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

22 Jul 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).


to complain fretfully

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