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reaction

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reaction/riˈækʃən/noun
pluralreactions
reaction
/riˈækʃən/
noun
pluralreactions
Learner's definition of REACTION  
: the way someone acts or feels in response to something that happens, is said, etc.
[count]
[noncount]
: an action or attitude that shows disagreement with or disapproval of someone or something
[count]
— usually singular— often + against
[noncount]
reactions [plural] : the ability to act and move quickly in order to avoid sudden danger
medical : an occurrence in which your body is affected by a drug, food, etc., in usually a bad way
[count]
[noncount]
chemistry : a chemical change that occurs when two or more substances combine to form a new substance
[count]
[noncount]
   b [count, noncount]physics : a process in which the nucleus of an atom is changed by being split apart or joined with the nucleus of another atom
— see also chain reaction
— called also nuclear reaction
[count, noncount]physics : a physical force that opposes the action of an equal and opposite force
[noncount]formal : a strong tendency or desire to oppose new political or social ideas
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