A pitch that is not a strike. There is a strike zone in baseball. (See Strike Zone) When a ball is above the batters knees but below his shoulders and over home plate, any part of home plate, that is a strike. So a baseball that does not do these things is called a ball. If a batter swings at a pitch and misses this is also a strike. If a batter hits a ball and it goes foul this is also a strike, unless the batter already has two strikes against him, then this just counts as a foul ball. Also remember the home plate umpire is calling balls and strikes and if the umpire calls a pitch a strike, then it is a strike. Disagreements do come about if a pitch was close as to whether or not the pitch was a ball or a strike, but the umpire always gets his way and arguing about a pitch very long at all will get a player tossed out of the game. Also remember if the batter gets 4 balls then they go to first base, but 3 strikes against a batter and they are out.