fosse

a long narrow channel dug in the earth the first line of defense is a water-filled fosse that enemy troops would have to cross Synonyms dike, ditch (or foss), gutter, sheugh [chiefly Scottish], trench, troughRelated Words acequia [Southwest], culvert, drain, draw, gully (also gulley), ravine; drill, furrow; ha-ha, moat, stank [British dialect], sunk fence; kennel