reaction ( reactions plural )
1 n-var Your reaction to something that has happened or something that you have experienced is what you feel, say, or do because of it.
usu with supp
Reaction to the visit is mixed..., He was surprised that his answer should have caused such a strong reaction.
2 n-count A reaction against something is a way of behaving or doing something that is deliberately different from what has been done before.
N against n
All new fashion starts out as a reaction against existing convention...
3 n-sing If there is a reaction against something, it becomes unpopular.
also no det, N against n
Premature moves in this respect might well provoke a reaction against the reform...
4 n-plural Your reactions are your ability to move quickly in response to something, for example when you are in danger.
oft poss N
The sport requires very fast reactions.
5 n-uncount Reaction is the belief that the political or social system of your country should not change., (disapproval)
Thus, he aided reaction and thwarted progress.
6 n-count A chemical reaction is a process in which two substances combine together chemically to form another substance.
Ozone is produced by the reaction between oxygen and ultra-violet light...
7 n-count If you have a reactionto a substance such as a drug, or to something you have touched, you are affected unpleasantly or made ill by it. oft adj N to n Every year, 5000 people have life-threatening reactions to anaesthetics...
chain reaction ( chain reactions plural )
1 n-count A chain reaction is a series of chemical changes, each of which causes the next.
2 n-count A chain reaction is a series of events, each of which causes the next.
The powder immediately ignited and set off a chain reaction of explosions.