reacted; reacting; reacts
1
: to change in response to a stimulus: such as
a
: to act or behave in a certain way in response to a situation, comment, etc.
When I told her what happened, she reacted with anger.
Most people reacted positively to the news.
The firefighters reacted quickly when they heard the alarm.
b
: to be or have a bodily response to something : to be or have a reaction (see reaction sense 3)
the way our bodies react to cold/pain
was not sure how the patient would react to the treatment
2
: to act in opposition to a force or influence
—usually used with against
a group of artists who reacted against convention
3
: to move or tend in a reverse direction
Stock prices reacted strongly after a brief drop.
4
: to exert a reciprocal or counteracting force or influence
—often used with on or upon
… his solitude … reacted on [=had an effect on] his character.—Henry Adams
5
: to undergo chemical reaction
: to cause to react
Cite this Entry
“React.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/react. Accessed 1 Sep. 2026.
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