(reacts, reacting, reacted)
Frequency: The word is one of the 3000 most common words in English.
1.
When you react to something that has happened to you, you behave in a particular way because of it.
They reacted violently to the news...
It's natural to react with disbelief if your child is accused of bullying...
= respond
VERB: V to n, V adv/prep, also V
2.
If you react against someone's way of behaving, you deliberately behave in a different way because you do not like the way they behave.
My father never saved and perhaps I reacted against that.
= rebel
VERB: V against n
3.
If you react to a substance such as a drug, or to something you have touched, you are affected unpleasantly or made ill by it.
Someone allergic to milk is likely to react to cheese...
VERB: V to n, also V
4.
When one chemical substance reacts with another, or when two chemical substances react, they combine chemically to form another substance.
Calcium reacts with water...
Under normal circumstances, these two gases react readily to produce carbon dioxide and water.
V-RECIP: V with n, pl-n V