Trench

 
מַעְגָּל Strong’s #4570 magal

And David rose up early in the morning, and left the sheep with a keeper, and took, and went, as Jesse had commanded him; and he came to the trench, as the host was going forth to the fight, and shouted for the battle.

1 Samuel 17:20

https://biblehub.com/hebrew/4570.htm

When wagons are repeatedly driven down a path, the wheels cut grooves, ruts or trenches in the path. These grooves force wagons to follow this very same path time after time. For this reason, this word means a path that is well defined and easy to follow.