react
Americanverb (used without object)
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reacts,
present (3rd person singular)
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reacted,
past participle, past
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reacting
present participle
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to act in response to an agent or influence.
How did the audience react to the speech?
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to act reciprocally upon each other, as two things.
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to act in a reverse direction or manner, especially so as to return to a prior condition.
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to act in opposition, as against some force.
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to respond to a stimulus in a particular manner.
reacting to a shock by jumping; to react to the word “coward” with anger.
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to undergo a chemical reaction.
verb
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(intr; foll by to, upon etc) (of a person or thing) to act in response to another person, a stimulus, etc, or (of two people or things) to act together in a certain way
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to act in an opposing or contrary manner
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(intr) physics to exert an equal force in the opposite direction to an acting force
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chem to undergo or cause to undergo a chemical reaction
Other Word Forms
Inflected Forms
Participles
Conjugated Forms
Present
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reactsimple
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reactssimple
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have reactedperfect
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has reactedperfect
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am reactingprogressive
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are reactingprogressive
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is reactingprogressive
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have been reactingperfect progressive
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has been reactingperfect progressive
Past
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reactedsimple
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had reactedperfect
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was reactingprogressive
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were reactingprogressive
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had been reactingperfect progressive
Future
Etymology
Origin of react
First recorded in 1635–45; re- + act, probably modeled on Medieval Latin reagere
Explanation
When you react to something, you respond to it. If someone pokes you in class, you might react by sticking out your tongue at them. The teacher might then react by giving you both detention. If someone says to you, "act, don't react," they are telling you not to automatically respond to something that someone does. Instead, you should think about it first and then decide what you want to do. In science, the word react is used to describe what happens when two substances combine and cause a chemical change in each other. When you add baking soda to vinegar, the chemicals in each react and create a foamy lava like substance.
Vocabulary lists containing react
Academic Vocabulary Toolkit 1, Words 71-80
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Word Generation Weekly - Series 1
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"Building Bridges" and "The Right Words at the Right Time"
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
“When you see an 87-year-old being evicted from her home 99.9% of people react negatively, everyone shows solidarity. But this case is more complicated,” said de la Cruz.
From The Wall Street Journal ● Oct. 8, 2026
Whether this happens depends a bit on how stock prices react to the higher rates — something that is more ambiguous.
From MarketWatch ● Oct. 8, 2026
Known as the hybrid model, it predicts that quark-gluon plasma should react like a fluid when energetic particles travel through it.
From Science Daily ● Oct. 6, 2026
"Over the last 12 months we've seen a rise of up to 50p a litre, excluding VAT, and it's hard to react to that, because of how we deal with our customers," he said.
From BBC ● Oct. 2, 2026
Nobody else knew how to react, and they basically looked at each other like, Is she serious or joking?!
From "The Science of Breakable Things" by Tae Keller
On Earth, when water reacts with olivine, the process can produce hydrogen that certain microbes can use as an energy source.
From Science Daily ● Sep. 30, 2026
The Tesla’s cameras can see jaywalkers before I do, oncoming headlights don’t blind it, and the car reacts faster than I can.
From The Wall Street Journal ● Aug. 4, 2026
As that acidic water reacts with certain rocks -- limestone, for instance -- it releases carbon dioxide into the atmosphere.
From Barron's ● Jul. 22, 2026
Finally, as with all previous administrations, how a Burnham-led government reacts to events beyond its control may have the biggest impact on the money in people's pockets.
From BBC ● Jul. 20, 2026
He reacts to the fear in his parents’ voices because his parents hold up the world for him and he has no protection without them.
From "The Fire Next Time" by James Baldwin
Russian authorities denied Tuesday that they were imposing anti-plague measures after a laboratory technician reportedly died of the disease, and reacted to Washington's offer of assistance by proposing to help battle US infectious diseases.
From Barron's ● Oct. 6, 2026
Schneider said the deal complements its own industrial AI data foundation, but investors reacted negatively, as Schneider stock fell 8% in early Paris trade.
From MarketWatch ● Oct. 5, 2026
But Lee and Marriott's research has found that consumers often reacted negatively to AI-generated models once they realised they were not real.
From BBC ● Oct. 3, 2026
The New York Times, using campus police documents and witness statements, laid out the timeline showing that she initially reacted with confusion and shame.
From Salon ● Oct. 2, 2026
I wanted to ask Red more about her granny and the things she had said to me, but I didn’t dare, not with the way she’d reacted when I said her granny was strange.
From "Rump: The (Fairly) True Story of Rumpelstilskin" by Liesl Shurtliff
At the same time, water molecules surrounding the reacting molecules constantly shift and reorganize in ways that are notoriously difficult to observe directly.
From Science Daily ● Oct. 6, 2026
"I was just reacting to what was going on," he said.
From BBC ● Oct. 4, 2026
Prosecutors have said Linton was pretending to seize during the tests, noting the scan itself did not show brain activity consistent with an epileptic episode during the moments when she was physically reacting.
From Los Angeles Times ● Oct. 1, 2026
“At least someone is reacting to surging energy prices and interest rates.”
From The Wall Street Journal ● Sep. 25, 2026
Gradually, he learned the details of my condition, reacting to them in a milder way than my parents had, which allowed them, or at least Tessie, to begin to accept the new reality.
From "Middlesex: A Novel" by Jeffrey Eugenides
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
