react

verb

re·​act rē-ˈakt How to pronounce react (audio)
reacted; reacting; reacts
Synonyms of reactnext

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

Synonyms of react

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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.
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
By identifying exactly what the frustration concerns before reacting, leaders are more likely to channel emotion toward fixing broken systems instead of attacking individuals. — Rodger Dean Duncan, Forbes.com, 13 Aug. 2026 At one time, scientists didn’t think that significant quantities of free oxygen, or O2, would be found anywhere else on the planet, in part because O2 reacts aggressively with other elements. — James Dinneen, New Yorker, 13 Aug. 2026 Lessons learned in a disaster's aftermath Much of the response depends on how the governments react. — Luis Giraldo, CBS News, 13 Aug. 2026 This enables teams to quickly adapt to demand shifts instead of reacting post-disruption after stockouts or excess inventory situations have already occurred. — Arthur Zaczkiewicz, Footwear News, 13 Aug. 2026 See All Example Sentences for react

Word History

Etymology

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

First Known Use

1644, in the meaning defined at intransitive sense 1

Time Traveler
The first known use of react was in 1644

Phrases Containing react

Rhymes for react

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Browse Nearby Words

reacquisition
react
react against
See all Nearby Words

Cite this Entry

“React.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/react. Accessed 16 Aug. 2026.

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Kids Definition

react

verb
re·​act rē-ˈakt How to pronounce react (audio)
1
: to act or behave in response (as to stimulation or an influence)
the colonists reacted to the tax by boycotting tea
2
: to oppose a force or influence
—usually used with against
reacted against their unfair treatment
3
: to go through or cause to go through a chemical reaction

Medical Definition

react

intransitive verb
re·​act rē-ˈakt How to pronounce react (audio)
1
: to respond to a stimulus
2
: to undergo chemical reaction

transitive verb

: to cause to react

More from Merriam-Webster on react

Nglish: Translation of react for Spanish Speakers

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