A bullpen or bull pen may refer to:
Literally, a pen or enclosure for bulls In baseball, the bullpen, an area for pitchers to warm up, also the location of relief pitchers A fortified ridge at the Siege of Port Hudson Broadly, any group of people kept together or in reserve for a common goal, such as the staff of Marvel Comics' Bullpen Bulletins
Open areas holding large groups of people, such as: The bull pen or bull system, where Australian waterfront workers' under the Dog collar act were hired for the day An open plan office layout, especially that of local law enforcement The fan zone of NRG Stadium A round pen with solid-walled sides for training horses A holding cell that contains a large number of prisoners A prison yard or open area where prisoners are held An open area in a prison camp A system of prostitution, credited to Jean O'Hara, where a single prostitute would work three rooms in rotation
See also Toril (disambiguation)