From WordNet (r) 2.0 (August 2003) [wn]:
baseball
n 1: a ball game played with a bat and ball between two teams of
9 players; teams take turns at bat trying to score run;
"he played baseball in high school"; "there was a
baseball game on every empy lot"; "there was a desire
for National League ball in the area"; "play ball!"
[syn: baseball game, ball]
2: a ball used in playing baseball
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Baseball \Base"ball"\, n.
1. A game of ball, so called from the bases or bounds (four
in number) which designate the circuit which each player
must endeavor to make after striking the ball.
[1913 Webster]
2. The ball used in this game.
[1913 Webster]