Baseball, a game played with a bat, a ball, and gloves between two teams of nine players each on a field with four white bases laid out in a diamond (i.e., a square oriented so that its diagonal line is vertical). Teams alternate positions as batters (offense) and fielders (defense), exchanging places when three members of the batting team are “put out.” As batters, players try to hit the ball out of the reach of the fielding team and make a complete circuit around the bases for a “run.” The team that scores the most runs in nine innings (times at bat) wins the game.