The foul lines, often colored white or yellow, partially outline the field of play. They extend from the batter's box to the foul poles located deep into left field and right field. Inside of the lines is fair, and outside is foul.
The baselines are the straight lines in between each of the bases. The baselines between 1st base and 2nd base, and 2nd base and 3rd base are invisible and not marked on a baseball field. However, the baselines between home plate and 1st base, and 3rd base and home plate coincide with the foul line. The baselines are important for base running.
The running lane is a 3ft wide lane on the field next to the foul line and first base. It is used as a marker for batters running towards first base. The batter must keep both feet inside or on the lines of the running lane when advancing to first base from home plate. When the base runner is close to first base, he is allowed to step out of the running lane with a slide or large step. At the discretion of the umpire the base runner can be called for interference and an out.
There is a box just outside of the foul lines by first base and third base where a coach from the offense stands in. They are called the first base coach and third base coach. These coaches are required to wear helmets and must remain inside the coaches' boxes unless they are giving direction to base runners. Base coaches also exchange equipment between the base runners such as giving them a helmet and taking the bat off the field.
The batter's box is an area at home plate that the batter takes position in during his at bat. Once the pitcher begins his motion, the batter is not allowed to leave the batter's box. The batter can call "time" between pitches to leave the batter's box temporarily.
The catcher is positioned in the catcher's box at the back of home plate. The catcher can leave this box any time to field the ball, but must remain inside the catcher's box on a pitch or he risks being called for a balk.