1. any game played with a ball, esp. baseball or softball.
2. Informal.a situation and all its attendant circumstances: Having a new administration in power changes the entire ball game at city hall. Cf. new ball game.
3. Archaeol.a ceremonial game of both ritual and sporting significance, played by teams on a ball court in Mesoamerican cultures from the Preclassic period to the Spanish conquest. Also,ball'game".
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.