gaol

1. A place or institution for the confinement of persons held in lawful custody or detention, especially for minor offenses or with reference to some future judicial proceeding.
2. Confinement in a jail.
3. The condition created by the requirement that a horse claimed in a claiming race not be run at another track for some period of time (usually 30 days).
4. In dodgeball and related games, the area where players who have been struck by the ball are confined.
5. (FreeBSD) A kind of sandbox for running a guest operating system instance.

verb

To imprison.