bullpen

Short definition from Wiktionary

Noun

1. 1
   An enclosed area used to hold bulls.
2. 2
   An enclosed area for pitchers to warm up in during a game.
3. 3
   The relief pitchers of a team collectively.
4. 4
   A place for someone or something to get ready.
5. 5
   An open seating arrangement where project teams can communicate openly with minimal effort.
6. 6
   A military prison or its enclosing stockade.