reaction
noun
re·ac·tion
rē-ˈak-shən 
1
a
: the act or process or an instance of reacting
b
: resistance or opposition to a force, influence, or movement
especially
: tendency toward a former and usually outmoded political or social order or policy
2
: a response to some treatment, situation, or stimulus
her stunned reaction to the news
also
: such a response expressed verbally
critical reaction to the play
3
: bodily response to or activity aroused by a stimulus:
a
: an action induced by vital resistance to another action
especially
: the response of tissues to a foreign substance (such as an antigen or infectious agent)
b
: depression or exhaustion due to excessive exertion or stimulation
c
: heightened activity and overaction succeeding depression or shock
d
: a mental or emotional disorder forming an individual's response to his or her life situation
4
: the force that a body subjected to the action of a force from another body exerts in the opposite direction
5
a(1)
: chemical transformation or change : the interaction of chemical entities
(2)
: the state resulting from such a reaction
b
: a process involving change in atomic nuclei
Examples of reaction in a Sentence
Their reaction to the news was positive.
When I told him what happened, his immediate reaction was one of shock.
The announcement produced an angry reaction from most of the people at the meeting.
My first reaction when I met him was not to trust him.
There hasn't yet been much reaction to the announcement.
There has been strong reaction against the government's policies.
A good driver has quick reactions.
The speed of his reactions saved his life.
Recent Examples on the Web
Read more about the reaction among current and former Justice Department officials.
—
Elizabeth Robinson, NBC News, 14 Nov. 2024
Hilariously, Bynum had his head in his iPhone after the game, basking in the reaction to his latest viral moment on social media.
—Dane Mizutani, Twin Cities, 11 Nov. 2024
Up Lily-Rose Depp, Nosferatu Surprise, surprise — many of the early Nosferatu reactions are spotlighting Depp, who’s got the Winona Ryder/Isabelle Adjani/Greta Schröder role of the vampire’s muse.
—Nate Jones, Vulture, 9 Nov. 2024
The dog's unexpected reaction has come as a surprise to some, as pets tend to experience significant distress and anxiety during firework displays.
—Thomas G. Moukawsher, Newsweek, 5 Nov. 2024
See all Example Sentences for reaction 
Examples are automatically compiled from online sources to
show current usage.
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Opinions expressed in the examples do not represent those of Merriam-Webster or its editors.
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Elizabeth Robinson, NBC News, 14 Nov. 2024
Hilariously, Bynum had his head in his iPhone after the game, basking in the reaction to his latest viral moment on social media.
—Dane Mizutani, Twin Cities, 11 Nov. 2024
Up Lily-Rose Depp, Nosferatu Surprise, surprise — many of the early Nosferatu reactions are spotlighting Depp, who’s got the Winona Ryder/Isabelle Adjani/Greta Schröder role of the vampire’s muse.
—Nate Jones, Vulture, 9 Nov. 2024
The dog's unexpected reaction has come as a surprise to some, as pets tend to experience significant distress and anxiety during firework displays.
—Thomas G. Moukawsher, Newsweek, 5 Nov. 2024
See all Example Sentences for reaction
Dictionary Entries Near reaction
Cite this Entry
“Reaction.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/reaction. Accessed 28 Nov. 2024.
Copy CitationKids Definition
reaction
noun
re·ac·tion
rē-ˈak-shən
1
a
: the act or process or an instance of reacting
our reaction to the news
b
: an action or attitude opposing current political or social forces or ideas
2
: a bodily response to a stimulus
especially
: the response of the body to a foreign substance (as a drug)
3
: the force that opposes the action of a force applied to one body by another body
4
a
: chemical transformation or change : the action between atoms or molecules to form one or more new substances
b
: a process involving change in atomic nuclei
Medical Definition
reaction
noun
re·ac·tion
rē-ˈak-shən
1
: the act or process or an instance of reacting
2
: bodily response to or activity aroused by a stimulus:
a
: an action induced by vital resistance to another action
especially
: the response of tissues to a foreign substance (as an antigen or infectious agent)
b
: depression or exhaustion due to excessive exertion or stimulation
c
: abnormally heightened activity succeeding depression or shock
d
: a mental or emotional disorder forming an individual's response to his or her life situation
3
: the force that a body subjected to the action of a force from another body exerts in the opposite direction
4
a(1)
: chemical transformation or change : the interaction of chemical entities
(2)
: the state resulting from such a reaction
b
: a process involving change in atomic nuclei
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