react

American  

[ree-akt] / riˈækt /

verb (used without object)

1. to act in response to an agent or influence.

   How did the audience react to the speech?

2. to act reciprocally upon each other, as two things.

3. to act in a reverse direction or manner, especially so as to return to a prior condition.

4. to act in opposition, as against some force.

5. to respond to a stimulus in a particular manner.

   reacting to a shock by jumping; to react to the word “coward” with anger.

6. to undergo a chemical reaction.

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react British  

/ rɪˈækt /

verb

1. (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

2. to act in an opposing or contrary manner

3. (intr) physics to exert an equal force in the opposite direction to an acting force

4. chem to undergo or cause to undergo a chemical reaction

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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.

Example Sentences

Sterner tests await, of course, with the fate of weekend talks likely to define the market’s next moves, particularly if oil prices react more dramatically to the strait’s continuing closure.

From Barron's • Apr. 10, 2026

That left him wondering: “How do you react when you turn on the TV and CNN is reporting your death?”

From Los Angeles Times • Apr. 9, 2026

That ability to react in real time to shoppers’ preferences may be more of a challenge as Revolve goes offline to some extent.

From The Wall Street Journal • Apr. 3, 2026

Every week you will be judged on your result and, no matter what philosophy you employ, the fanbase and the people above you will react accordingly.

From BBC • Apr. 3, 2026

Yet Nicholas was not declared a heretic, and the church didn’t react to the new idea.

From "Zero: The Biography of a Dangerous Idea" by Charles Seife

Related Words

• acknowledge
• act
• answer
• behave
• counter
• feel
• perform
• proceed
• reply
• revert