contravallation

Contravallation \Con`tra*val*la"tion\, n. [Pref. contra- +
   vallation: cf. F. contrevallation. Cf. {Countervallation}.]
   (Fort.)
   A trench guarded with a parapet, constructed by besiegers, to
   secure themselves and check sallies of the besieged.
   [1913 Webster]
    

56 Moby Thesaurus words for "contravallation":
      abatis, advanced work, balistraria, bank, banquette,
      barbed-wire entanglement, barbican, barricade, barrier, bartizan,
      bastion, battlement, breastwork, bulwark, casemate,
      cheval-de-frise, circumvallation, counterscarp, curtain,
      demibastion, dike, drawbridge, earthwork, enclosure, entanglement,
      escarp, escarpment, fence, fieldwork, fortalice, fortification,
      glacis, loophole, lunette, machicolation, mantelet, merlon, mound,
      outwork, palisade, parados, parapet, portcullis, postern gate,
      rampart, ravelin, redan, redoubt, sally port, scarp, sconce,
      stockade, tenaille, vallation, vallum, work