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 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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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
Most incidents can be blamed on inattention and poor reactions. — John Schandelmeier, Anchorage Daily News, "When sharing the backcountry with bears, choose a shotgun as your companion," 20 Aug. 2019 Goals from Sadio Mané and Roberto Firmino settled the game, and Jurgen Klopp will be thrilled with his players' reaction to their 120-minute test in Istanbul on Wednesday evening. — SI.com, "Southampton 1-2 Liverpool: Report, Ratings & Reaction as Risky Reds Edge Past Saints," 17 Aug. 2019 Methane doesn’t stay in the atmosphere as long as CO2 and is reabsorbed into terrestrial cycles via chemical reactions within 12 years or so. — David Roberts, Vox, "Fracking may be a bigger climate problem than we thought," 16 Aug. 2019 Congressional reaction Israel’s decision to ban the two freshman lawmakers was a step too far for many members of Congress, even some who are still wary of Tlaib and Omar’s positions on Israel. — Alana Abramson, Time, "How Israel's Travel Ban on Reps. Omar and Tlaib Is Uniting Democrats — Including Their Critics," 16 Aug. 2019 Fortunately for the Rock Hall, any reactions to the concert will likely turn mute by the time the nominations for the Class of 2020 arrive this fall. — cleveland.com, "Rock and Roll Hall of Fame’s new ‘Rock Hall Honors’ series is already a huge letdown," 16 Aug. 2019 The man who was punched seemed to show little reaction to the blow in the video. — Claudia Harmata, PEOPLE.com, "Conor McGregor Reportedly Hit a Man for Refusing a Shot of His Whiskey," 15 Aug. 2019 Advertising billboards assess consumers’ reactions to their contents. — The Economist, "As face-recognition technology spreads, so do ideas for subverting it," 15 Aug. 2019 Journaling is great way to recognize and reflect on your emotions and reactions. — al, "Birmingham high schoolers to receive mental health kits thanks to local effort," 14 Aug. 2019These 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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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
: the ability to act and move quickly in order to avoid sudden danger
See the full definition for reaction in the English Language Learners Dictionary
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 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