What is a bullpin?

A bullpen is the area in a baseball field where relief pitchers warm up before entering a game. The term "bullpen" originated in the late 19th century when pitchers would warm up in a area just beyond the outfield fence, which was often home to grazing bulls. The area has since moved closer to the field of play and is usually located in foul territory beyond the outfield fence. Bullpens typically have mounds and pitching rubbers, as well as areas for catchers and pitching coaches to observe and analyze the pitchers' warm-up routines. In addition to warming up before games, pitchers may also use the bullpen to throw bullpen sessions to simulated game situations.