reaction

noun
re·​ac·​tion | \ rē-ˈak-shən \

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 infective 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

answer, reply, response, take

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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

But the cars needed to drive 20 percent slower to match the reaction time of a human driver at 25 mph. Andrew J. Hawkins, The Verge, "Uber’s self-driving cars return to public roads for the first time since fatal crash," 20 Dec. 2018 This time, instead of being a reaction to ’80s excess, the trend was a response to the flipper mentality of pre-crash America, which saw home renovation as a guaranteed gold mine. Laura Fenton, Curbed, "How the ‘modern farmhouse’ look took over," 21 Nov. 2018 One of the most interesting things about this moment is Kevin’s reaction. Candice Frederick, Harper's BAZAAR, "This Is Us Reveals Zoe’s Heartbreaking Trauma," 14 Nov. 2018 Joining us now for reaction is former Trump campaign manager, Corey Lewandowski, Lee Smith from RealClear Investigations and former U.S. attorney, Kendall Coffey. Fox News, "What role has Rosenstein played in decision to declassify?," 21 Sep. 2018 Duhé joined the producer on stage to belt the pop-ballad, and fans reaction was pretty favorable. Kat Bein, Billboard, "Zedd Announces New Collaboration 'Happy Now' With Elley Duhe," 13 July 2018 Vlade Divac’s reaction is great Auguste hopes his play draws the attention of a team that will give him a chance to play in the NBA after summer league stints with the Lakers (2016) and Miami (2017). Jason Jones, sacbee, "Mistaken for other rising stars, can Zach Auguste make a name for himself with Kings?," 12 July 2018 Fans were atwitter on Twitter because of Kufrin’s reaction. Alison Bowen, chicagotribune.com, "So how do you tell someone you're a virgin? 'Bachelorette' spurs conversation," 10 July 2018 Martin’s attempt to sound white and the operator’s reaction shrewdly emphasize how the perception of whiteness grants a measure of access often closed to people of color. Aisha Harris, New York Times, "When Black Performers Use Their ‘White Voice’," 10 July 2018

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

10 Jan 2019

Look-up Popularity

Time Traveler for reaction

The first known use of reaction was in 1585

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More Definitions for reaction

reaction

noun

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

reactions : the ability to act and move quickly in order to avoid sudden danger

reaction

noun
re·​ac·​tion | \ rē-ˈak-shən \

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 \

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 infective 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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