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
Listen to the eclipse 😎 Internet's 2017 reaction to Trump staring at eclipse
On the day of the 2017 eclipse, Trump's actions nearly broke the internet.
—
USA TODAY, 7 Apr. 2024
On a later release, Smith used a sample of her mom's voice, which Brandy herself was very proud of and shared her reaction to on Instagram.
—Vandana Pawa, Peoplemag, 6 Apr. 2024
So far, most of the information on animal reactions to an eclipse is anecdotal, but there are scientific efforts to make systematic observations.
—Geraldine Castro, WIRED, 6 Apr. 2024
Four years ago, this policy seemed like a thoughtful reaction to the first Trump election, when extensive unmediated coverage of his rallies played like advertisements for the man.
—Jay Caspian Kang, The New Yorker, 5 Apr. 2024
To sieve only the sound of a performance is to miss out on a world of visual and atmospheric cues, from body language to lighting to set design, not to mention audience reaction.
—Rhoda Feng, New York Times, 4 Apr. 2024
Much of their reaction was rooted in the atmosphere of the ‘70s and ‘80s as women were fighting for gender equality on several fronts from work to reproductive rights.
—Shalene Gupta, TIME, 4 Apr. 2024
The decision to vacate the board has drawn strong reactions from TSU supporters and students, with some expressing disappointment and frustration at the Legislature’s response to the university’s challenges.
—Melissa Noel, Essence, 4 Apr. 2024
The news about Bickle on Friday night drew swift reaction from former IHOPKC leaders.
—Judy L. Thomas, Kansas City Star, 25 Mar. 2024
USA TODAY, 7 Apr. 2024
On a later release, Smith used a sample of her mom's voice, which Brandy herself was very proud of and shared her reaction to on Instagram.
—Vandana Pawa, Peoplemag, 6 Apr. 2024
So far, most of the information on animal reactions to an eclipse is anecdotal, but there are scientific efforts to make systematic observations.
—Geraldine Castro, WIRED, 6 Apr. 2024
Four years ago, this policy seemed like a thoughtful reaction to the first Trump election, when extensive unmediated coverage of his rallies played like advertisements for the man.
—Jay Caspian Kang, The New Yorker, 5 Apr. 2024
To sieve only the sound of a performance is to miss out on a world of visual and atmospheric cues, from body language to lighting to set design, not to mention audience reaction.
—Rhoda Feng, New York Times, 4 Apr. 2024
Much of their reaction was rooted in the atmosphere of the ‘70s and ‘80s as women were fighting for gender equality on several fronts from work to reproductive rights.
—Shalene Gupta, TIME, 4 Apr. 2024
The decision to vacate the board has drawn strong reactions from TSU supporters and students, with some expressing disappointment and frustration at the Legislature’s response to the university’s challenges.
—Melissa Noel, Essence, 4 Apr. 2024
The news about Bickle on Friday night drew swift reaction from former IHOPKC leaders.
—Judy L. Thomas, Kansas City Star, 25 Mar. 2024
These examples are programmatically compiled from various online sources to illustrate current usage of the word 'reaction.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.
Dictionary Entries Near reaction
Cite this Entry
“Reaction.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/reaction. Accessed 17 Apr. 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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