Source : Webster's Revised Unabridged Dictionary (1913)

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.

   2. The ball used in this game.

Source : WordNet®

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