Glacis (allied to glade in the sense of a lawn) is the slope of earth, generally 1 in 20, which inclines from the Covered-way (q.v.) of a fortress towards the country. It obliges the assailants to approach over an open space swept by fire from the fortress, and at the same time masks the general works of the place. See FORTIFICATION.
Glacis
Chambers's Encyclopaedia, Volume 5: Friday to Humanitarians, p. 225
Source scan(s): p. 0236