reaction Definition in the Cambridge English Dictionary
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Definition of “reaction” - English Dictionary

Definition of "reaction" - American English Dictionary

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reactionnoun [C]

 us   /riˈæk·ʃən/
behavior, a ​feeling, or an ​action that is a ​directresult of something ​else: My ​initial reaction was to ​call off the ​party. Senator, what is ​your reaction to the ​proposal to ​cutMedicarebenefits? A reaction is also a ​change that ​opposes a ​previousopinion or ​behavior: His ​art is a reaction against ​photographicrealism. biology A reaction can also be an ​unpleasanteffect on the ​body resulting from something ​eaten or taken, such as a ​drug. chemistry A ​chemical reaction is the ​change that ​happens when two or more ​substances are ​mixed with each other.
(Definition of reaction from the Cambridge Academic Content Dictionary © Cambridge University Press)

Definition of "reaction" - British English Dictionary

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reactionnoun

uk   us   /riˈæk.ʃən/

reaction noun (BEHAVIOUR)

B2 [C] behaviour, a ​feeling or an ​action that is a ​directresult of something ​else: I ​love to ​watch people's reactions when I say who I am. There has been an ​immediate/​widespread/​hostile reaction against the government's ​proposedtaxincreases. Reactions to the ​proposal so ​far have been ​adverse/​favourable/​mixed.reactions [plural] someone's ​ability to ​actquickly when something ​happens: You need to have quick reactions to ​play these ​computergames. [C usually singular] a ​type of ​behaviour or ​opinion that is ​produced or ​held with the ​intention of being different from something ​else: Her ​left-wingviews are a reaction against the ​conservatism of her ​parents.
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reaction noun (UNPLEASANT EFFECT)

B2 [C] an ​unpleasanteffectresulting from ​eatingparticular things or taking ​particulardrugs: Some ​people have an allergic reaction toshellfish.

reaction noun (IN SCIENCE)

[C or U] chemistry an ​occasion when two or more ​substancesreact with and ​change each other: a chemical reaction

reaction noun (NO CHANGE)

[U] disapproving the ​belief or ​principle that there should be no ​social or ​politicalchange, and the ​attempt to ​stop such ​change from ​happening: We must not ​allow reaction to ​stand in the way of ​progress.
(Definition of reaction from the Cambridge Advanced Learners Dictionary & Thesaurus © Cambridge University Press)

Definition of "reaction" - Business English Dictionary

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reactionnoun [C or U]

uk   us   /riˈækʃən/
the way that something ​happens, or that someone does something, as a ​result of something else: reaction to sth We've seen little ​market reaction to the latest ​inflationfigures.reaction against sth There was an immediate reaction against the ​proposedtaxincreases.
(Definition of reaction from the Cambridge Business English Dictionary © Cambridge University Press)
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