Dictionary.net

A narrow space between the foot of the rampart and the scarp of the ditch, serving to receive the earth that may crumble off or be washed down, and prevent its falling into the ditch.

A narrow space between the foot of the rampart and the scarp of the ditch, serving to receive the earth that may crumble off or be washed down, and prevent its falling into the ditch.

re-l[=a]', n. (fort.) a walk left within a rampart to keep earth from falling into the ditch. [Fr.]