react

verb

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

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

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.
Fans were quick to react to the intimate performance Twain gave. Marina Watts, People.com, 28 May 2025 For traders who respond to events, historical trends may present a favorable position, whether by preparing in advance of earnings or reacting to movements after the release. Trefis Team, Forbes.com, 28 May 2025 Reframe Weed As Wellness Shine your light on the good instead of being on the defense, reacting or responding to what is false. Lindsey Bartlett, Rolling Stone, 27 May 2025 Those researchers were using that technology to study how certain organs react to radiation therapy. Solcyré Burga, Time, 27 May 2025 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

Cite this Entry

“React.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/react. Accessed 1 Jun. 2025.

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

Last Updated: - Updated example sentences
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