WordWeb Online

1. [N. Amer] A place on a baseball field where relief pitchers can warm up during a game
    
2. [N. Amer] A large cell where prisoners (people awaiting trial, sentence, refugees or illegal immigrants) are confined together temporarily
   - detention cell, detention centre [Brit, Cdn], detention center [US]
    
3. An enclosed area used to hold bulls

Derived forms: bullpens

Type of: area, cell, jail cell, peter [Austral, NZ, informal], prison cell

Part of: ballpark [N. Amer], park

Encyclopedia: Bullpen