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.
Pakistan reacted with fury to the strikes and conducted retaliatory air and artillery strikes against positions tied to the Balochistan Liberation Army and Balochistan Liberation Front separatist groups in Iran's Sistan and Baluchestan province. Tom O'Connor, MSNBC Newsweek, 21 June 2025 However, some produce doesn’t react the right way to colder temperatures. Jessica Farthing, Southern Living, 21 June 2025 The craft reacted to the pressure signature by powering off the thrusters. ArsTechnica, 21 June 2025 Mahmoud Khalil, left, reacts alongside his wife, Noor Abdalla, right, upon arriving at Newark International Airport, Saturday, June 21, 2025, in Newark, N.J. Jesse Zanger, CBS News, 21 June 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 25 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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