in a general sense, denotes something posted or situated before another. Thus,

ADVANCED Ditch, in fortification, is that which surrounds the glacis or esplanade of a place.

ADVANCED Guard, or Vanguard, in the art of war, Advanced the first line or division of an army, ranged or marching in order of battle; or, it is that part which is next the enemy, and marches first towards them.

Advanced Guard, is more particularly used for a small party of horse stationed before the main-guard.