A broad strip of dirt on a baseball field just beyond the grass that runs parallel to the ballpark walls.
The warning track is used as a safety measure to signal to players that they are close to a wall or other obstacle when they are making a play. The transition between field and track is seamless and allows players some time to slow down and judge how much space they have remaining to safely field a ball. The term "warning track" originated at the Old Yankee Stadium, as an actual track was constructed for track and field competitions. Every ballpark soon followed suit, adopting warning tracks as they are used today.