noun (n)

• a platform built out from the shore into the water and supported by piles; provides access to ships and boats(noun.artifact)

  Synonym:
  dock, wharf, wharfage
  

  source: wordnet30
• (architecture) a vertical supporting structure (as a portion of wall between two doors or windows)(noun.artifact)

  source: wordnet30
• a support for two adjacent bridge spans(noun.artifact)

  source: wordnet30
• Any detached mass of masonry, whether insulated or supporting one side of an arch or lintel, as of a bridge; the piece of wall between two openings.(noun)

  source: webster1913