reaction

noun
re·​ac·​tion | \ rē-ˈak-shən How to pronounce reaction (audio) \

Definition of reaction

1a : 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
5a(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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Synonyms for reaction

Synonyms

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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.
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Recent Examples on the Web Benitez said of his guests’ reactions to Prince Michael’s presence. Kelli Bender, PEOPLE.com, "Groom Loves His Cat So Much, He Made the Feline His Best Man," 17 Sep. 2019 Many people also tweeted their reactions to his bold shirt. Fox News, "Trump calls for resignations at NY Times over Kavanaugh story; Netanyahu's challenge in repeat election," 17 Sep. 2019 Instead, over the past year the most notable collaboration between Nike and Kaepernick was his reaction to the creation of another shoe. Kevin Draper, New York Times, "Colin Kaepernick ‘Dream Crazy’ Ad Wins Nike an Emmy," 16 Sep. 2019 Have you been successfully conned into believing that your own honest reactions are not acceptable? Amy Dickinson, Washington Post, "Ask Amy: Old-fashioned values are out with the trash," 15 Sep. 2019 Have you been successfully conned into believing that your own honest reactions are not acceptable? Amy Dickinson, The Denver Post, "Ask Amy: Old-fashioned values are out with the trash," 15 Sep. 2019 Have you been successfully conned into believing that your own honest reactions are not acceptable? Amy Dickinson, The Mercury News, "Ask Amy: Our neighbors sneak their trash into our can. Is it petty that I’m upset?," 15 Sep. 2019 Never mind the suggestions – including my initial reaction earlier this week – that Brown should sit while the NFL investigated the allegations and use the exempt-list option as a pause button. Jarrett Bell, USA TODAY, "Opinion: Turns out the right thing is to let Antonio Brown play … pending further review," 13 Sep. 2019 The study suggests that your reaction to cannabis, positive or negative, is tied closer to your genetics than anything else. Brendan Bures, chicagotribune.com, "Marijuana makes you paranoid? Study suggests your genes are to blame," 13 Sep. 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'reaction.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of reaction

1585, in the meaning defined at sense 1a

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Statistics for reaction

Last Updated

31 Oct 2019

Time Traveler for reaction

The first known use of reaction was in 1585

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More Definitions for reaction

reaction

noun
How to pronounce reaction (audio)

English Language Learners Definition of reaction

: the way someone acts or feels in response to something that happens, is said, etc.
: an action or attitude that shows disagreement with or disapproval of someone or something
: the ability to act and move quickly in order to avoid sudden danger

reaction

noun
re·​ac·​tion | \ rē-ˈak-shən How to pronounce reaction (audio) \

Kids Definition of reaction

1 : behavior or attitude in response to something What was your reaction to the news?
2 : a response of the body to a stimulus He had an allergic reaction to peanuts.
3 : a chemical change that is brought about by the action of one substance on another and results in a new substance being formed

reaction

noun
re·​ac·​tion | \ rē-ˈak-shən How to pronounce reaction (audio) \

Medical Definition of reaction

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
4a(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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Comments on reaction

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