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:
In West Penwith, Mark said wildlife appeared to react to the changing light, with birds returning to their roosts as the eclipse took place.
From BBC ● Aug. 15, 2026
Scientists have struggled to directly investigate how their electrons move collectively, interact with one another, and react to outside disturbances.
From Science Daily ● Aug. 12, 2026
The most straightforward way of keeping your moods from affecting your portfolio is to have a detailed financial plan that, well in advance, specifies how you will react, come what may.
From MarketWatch ● Aug. 12, 2026
“The real answer is whether or not a bass will actually strike it…bass often react in ways that defy our imagination.”
From The Wall Street Journal ● Aug. 12, 2026
Belet didn't know how to react to that.
From "City of the Plague God" by Sarwat Chadda
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
The chemical deployed by Wallace during her investigation reacts with the iron in hemoglobin, a protein found in red blood cells.
From Los Angeles Times ● Jul. 22, 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 kind of reacts to crowds the same way he does hurricanes. And everything else.”
From "Two Degrees" by Alan Gratz
The artist reacted to the pardon on his Instagram story, saying that it “opens the door to a future I’ve worked hard for and I am fully prepared to step into this.”
From Los Angeles Times ● Aug. 13, 2026
The Fed held rates steady last month as broadly expected, but investors reacted with doubts when Warsh didn’t explain the decision.
From The Wall Street Journal ● Aug. 11, 2026
Many states reacted to the rise in exonerations by creating funds to compensate those who were wrongly convicted.
From Salon ● Aug. 10, 2026
On Wednesday evening, some of his victims reacted angrily to the letter.
From BBC ● Aug. 5, 2026
White America reacted to the lunch-counter sit-ins with equal parts alarm and confusion.
From "The Best of Enemies" by Osha Gray Davidson
Her voice breaks as she sings the lyric, "But I knew who I was when I got here", but it transpires that she's simply reacting to an audience member who's blubbing their eyes out.
From BBC ● Aug. 16, 2026
Micron stock was reacting to news that Apple has tested memory chips from China’s ChangXin Memory Technologies.
From Barron's ● Aug. 10, 2026
Rather than reacting only to familiar properties such as color or intensity, it detects subtle quantum distinctions in the incoming light.
From Science Daily ● Aug. 8, 2026
To be precise, Israel’s prime minister, Benjamin Netanyahu, has been hesitant in reacting to the plan.
From Los Angeles Times ● Aug. 7, 2026
It might give them the most disastrous ideas about the subject, might upset them into reacting in the entirely wrong, the utterly antisocial way.
From "Brave New World" by Aldous Huxley
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.
