The outfield, also known as the outfield grass, is the area in a baseball or softball field beyond the infield dirt. Synonyms for the outfield include the outfield area, the outfield territory, or the outfield zone. Additionally, it may be referred to simply as the outfield, the outfield sector, or the outfield region. In some cases, it may be colloquially called the "green monster" due to the seemingly endless expanse of grass. The outfield is an important part of the game, as it is where most of the action takes place, including tracking down fly balls and making critical defensive plays.