D defs.my
Entry 1 sense Webster, 1913

Glacis

/glās'-əs/ · Gla·cis · IPA /ˈɡleɪsɪs/
01 n. A gentle slope, or a smooth, gently sloping bank; especially (Fort.), that slope of earth which inclines from the covered way toward the ex…
  1. 1.
    A gentle slope, or a smooth, gently sloping bank; especially (Fort.), that slope of earth which inclines from the covered way toward the exterior ground or country (see Illust. of Ravelin).(Fort.) See: Ravelin