(1):

(n.) The glacis of the counterscarp, or the slope of the parapet of the covered way toward the country.

(2):

(n.) A grass plat; a lawn.

(3):

(n.) Any clear, level space used for public walks or drives; esp., a terrace by the seaside.

(4):

(n.) A clear space between a citadel and the nearest houses of the town.