esplanade

Short definition from Wiktionary

Noun

1. 1
   A clear space between a citadel and the nearest houses of the town.
2. 2
   The glacis of the counterscarp, or the slope of the parapet of the covered way toward the country.
3. 3
   A grass plat; a lawn.
4. 4
   Any clear, level space used for public walks or drives; especially, a terrace by the seaside.
5. 5
   Grassy strips between two divided highway lanes; a traffic island.