noun A place or institution where people are held against their will, in the US especially for long-term confinement, as of those convicted of serious crimes or otherwise considered undesirable by the government.
The cold stone walls of the prison had stood for over a century.
noun Confinement in prison (sense 1).
Prison was a harrowing experience for him.
noun Any restrictive environment, such as a harsh academy or home.
The academy was a prison for many of its students because of its strict teachers.