Definition (Cambridge Dictionary): 1. to limit an activity, person, or problem in some way; 2. to keep someone closed in a place, often by force.（指监禁或幽禁；也指任何使行动受到限制的行为）

Example:

The hostages had been confined for so long that they couldn't cope with the outside world.

人质被关押了那么久，以致于他们对外面的世界一时适应不了。

Keep the dog confined in a suitable travelling cage.

把狗关进适于旅行的笼子里。

Here the river is confined in a narrow channel.

这条河在这里流入狭窄的河床。

Definition (Cambridge Dictionary): to put someone in prison.（较正式用词，多指较长时间的监禁）

Example:

He was imprisoned in 1965 for attempted murder.

他因谋杀未遂于1965年被监禁。

Unable to go out because of the deep snow, she felt imprisoned in her own house.

她因雪深无法外出，感觉自己像被囚在了屋内。

Some young mothers feel imprisoned in their own homes.

有些年轻的母亲感到待在家里如同坐牢。

Definition (Cambridge Dictionary): a place where criminals are kept to punish them for their crimes, or where people accused of crimes are kept while waiting for their trials.（多指审判之间的拘禁或对罪行较轻的罪犯的监禁）

Example:

He was jailed for life for murder.

他因谋杀罪被终身监禁。

He was jailed for three years.

他被监禁了3年。