- bullpen (n.)
[bullpen 词源字典]
- also bull-pen, 1915, in the baseball sense, from bull (n.1) + pen (n.2); perhaps from earlier slang meaning "temporary holding cell for prisoners" (1809). Bullpen also was the name of a baseball-like game played in U.S. late 19c.[bullpen etymology, bullpen origin, 英语词源]