bullpen

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun An area where relief pitchers warm up during a game.
• noun The relief pitchers of a team considered as a group.
• noun A temporary holding area for prisoners, as in a courthouse.
• noun An open area in an office with workspace for a number of employees.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Baseball) 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.
• noun the relief pitchers on a baseball team. Contrasted with starters.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun An enclosed area used to hold bulls.
• noun baseball An enclosed area for pitchers to warm up in during a game.
• noun baseball The relief pitchers of a team collectively.
• noun metaphorical A figurative place for someone or something to get ready
• noun An open seating arrangement where project teams can communicate openly with minimal effort.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a large cell where prisoners (people awaiting trial or sentence or refugees or illegal immigrants) are confined together temporarily
• noun a place on a baseball field where relief pitchers can warm up during a game