1. bullpen(n = noun.artifact) - a place on a baseball field where relief pitchers can warm up during a game;
is a kind of area
is a part of ballpark, park
2. bullpen(n = noun.artifact) detention cell, detention centre - a large cell where prisoners (people awaiting trial or sentence or refugees or illegal immigrants) are confined together temporarily;
is a kind of cell, jail cell, prison cell
1. an open area in a baseball stadium, off the playing field, where pitchers may warm up by throwing a number of trial pitches before playing. [PJC]
2. the relief pitchers on a baseball team. Contrasted with