SAP n.
st parallel toward the glacis or covert way of a besieged place by digging under cover of gabions, etc. Sap fagot (Mil.), a fascine about three feet long, used in sapping, to close the crevices between the gabions before the parapet is made. -- Sap roller (Mil.), a large gabion, six or seven feet long, filled with fas…
TRENCH n.
e lines of approach. Trench cavalier (Fort.), 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 fur…