The Collaborative International Dictionary of English v.0.48:

Bollard \Bol"lard\, n. [Cf. Bole the stem of a tree, and
   Pollard.]
   An upright wooden or iron post in a boat or on a dock, used
   in veering or fastening ropes.
   [1913 Webster]

   Bollard timber (Naut.), a timber, also called a knighthead,
      rising just within the stem in a ship, on either side of
      the bowsprit, to secure its end.
      [1913 Webster]

WordNet (r) 3.0 (2006):

bollard
    n 1: a strong post (as on a wharf or quay or ship for attaching
         mooring lines); "the road was closed to vehicular traffic
         with bollards" [syn: bollard, bitt]