A baseball field, also called a better batter field or baseball diamond, is the field upon which the game of baseball is played. The term can also be used as a metonym for a baseball park.
Unless otherwise noted, the specifications discussed in this section refer to those described within the Official Baseball Rules, under which Major League Baseball is played. The plate is set into the ground so that its surface is level with the field. All the bases, including home plate, lie entirely within fair territory. Thus, any batted ball that touches those bases must necessarily be ruled a fair ball. Near the center of the square is an artificial hill known as the pitcher’s mound, atop which is a white rubber slab known as the pitcher’s plate, colloquially the “rubber”. The specifications for the pitcher’s mound are described below. The lines from home plate to first and third bases extend to the nearest fence, stand or other obstruction and are called the foul lines.
First base is the first of the four bases that must be touched by a runner in order to score a run for the batting team. The runner may continue running past first base in a straight line without being in jeopardy of being put out, so long as they make contact with first base and make no move or attempt to advance to second base. The first baseman is the defensive player mainly responsible for the area near first base. A first baseman is often tall. A tall first baseman has a larger range for reaching and catching errant throws.