prison
used as a countable noun
A prison is a building where criminals or other people are kept and are not allowed to leave.
The prison housed almost 500 inmates.
The castle was used as a prison at one time.
used as an uncountable noun
Prison is used without an article when talking about the punishment of going to prison, without mentioning which particular prison. For example, you can say that someone is in prison, is sent to prison, or is released from prison.
They were threatened with prison if they did not pay.
It can be hard to find work after coming out of prison.
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Be careful
Don't use ‘the’ in front of prison unless you are referring to a particular prison.
Don't use ‘the’ in front of prison unless you are referring to a particular prison.