-noun Dead Ball Out. In slow pitch softball when the maximum allowance of team homeruns has been met, any further homeruns will count as an out. Any homeruns exceeding the limit will be declared a dead ball out, or DBO, by the umpire. Frequently, DBO offenders can be quoted as saying "Screw the team, I'm going deep."
Swing lost the state championship for his team because he hit a game ending DBO with the tying run on third base.