(~s)
Frequency: The word is one of the 1500 most common words in English.
1.
Your ~ to something that has happened or something that you have experienced is what you feel, say, or do because of it.
Reaction to the visit is mixed...
He was surprised that his answer should have caused such a strong ~.
N-VAR: usu with supp
2.
A ~ against something is a way of behaving or doing something that is deliberately different from what has been done before.
All new fashion starts out as a ~ against existing convention...
N-COUNT: N against n
3.
If there is a ~ against something, it becomes unpopular.
Premature moves in this respect might well provoke a ~ against the reform...
N-SING: also no det, N against n
4.
Your ~s are your ability to move quickly in response to something, for example when you are in danger.
The sport requires very fast ~s.
N-PLURAL: oft poss N
5.
Reaction is the belief that the political or social system of your country should not change.
Thus, he aided ~ and thwarted progress.
N-UNCOUNT disapproval
6.
A chemical ~ is a process in which two substances combine together chemically to form another substance.
Ozone is produced by the ~ between oxygen and ultra-violet light...
N-COUNT
7.
If you have a ~ to a substance such as a drug, or to something you have touched, you are affected unpleasantly or made ill by it.
Every year, 5000 people have life-threatening ~s to anaesthetics...
N-COUNT: oft adj N to n