#ditch  a long narrow excavation in the earth
  supertype:  hole_in_the_ground__excavation  a hole in the ground made by excavating
  subtype:  drainage_ditch  a ditch for carrying off excess water or sewage
  subtype:  irrigation_ditch  a ditch to supply dry land with water artificially
  subtype:  sunk_fence__ha-ha__haw-haw__hawhaw  a ditch with one side being a retaining wall; used to divide lands without defacing the landscape
  subtype:  trench  a ditch dug as a fortification having a parapet of the excavated earth
     subtype:  approach_trench__communication_trench__communicationtrench  a trench that provides protected passage between the rear and front lines of a defensive position
     subtype:  fire_trench  a trench especially constructed for the delivery of small-arms fire
     subtype:  moat__fosse  ditch dug as a fortification and usually filled with water
     subtype:  slit_trench  narrow trench for shelter in battle
  subtype:  trench.ditch  any long ditch cut in the ground
     subtype:  furrow  a long shallow trench in the ground (especially one made by a plow)
        subtype:  gash__cut  a trench resembling a furrow that was made by erosion or excavation

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