Définitions
1.NounAn action or statement in response to a stimulus or other event."The announcement of the verdict brought a violent reaction.; You were in the courtroom. What is your reaction?; When I last tried to eat strawberries I had a terrible allergic reaction."
2.NounA transformation in which one or more substances is converted into another by combination or decomposition."In this reaction, the acid and base will neutralize each other, producing a salt."
3.NounReactionary politics; a period in which reactionary thought or politics is resurgent or dominant.
4.NounUnpurposeful behavior.
5.NounAn icon or emoji appended to a posted message by a user to express their feeling about it.