bol·lard 
(bŏlərd)
(bŏlərd)n.
1. Nautical A thick post on a ship or wharf, used for securing ropes and hawsers.
2. One of a series of posts preventing vehicles from entering an area.
3. A projecting bulge of snow or ice used as an anchor for a rope in mountaineering.
[Middle English, probably from bole, tree trunk; see BOLE1.]
bollard