3. An excavation made during a siege, for the purpose of covering the troops as they advance toward the besieged place. The term includes the parallels and the approaches. To open the trenches, an elevation constructed (by a besieger) of gabions, fascines, earth, and the like, about half way up the glacis, in order to discover and enfilade the covered way. Trench plow, or Trench plough, a kind of plow for opening land to a greater depth than that of common furrows.
Origin: OE. Trenche, F. Tranchee. See Trench.