The Collaborative International Dictionary of English v.0.48:

Navvy \Nav"vy\, n.; pl. Navies. [Abbreviated fr. navigator.]
   Originally, a laborer on canals for internal navigation;
   hence, a laborer on other public works, as in building
   railroads, embankments, etc. [Eng.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Navy \Na"vy\; n.; pl. Navies. [ OF. navie, fr. L. navis ship.
   See Nave of a church.]
   1. A fleet of ships; an assemblage of merchantmen, or so many
      as sail in company. "The navy also of Hiram, that brought
      gold from Ophir." --1 kings x. 11.
      [1913 Webster]

   2. The whole of the war vessels belonging to a nation or
      ruler, considered collectively; as, the navy of Italy.
      [1913 Webster]

   3. The officers and men attached to the war vessels of a
      nation; as, he belongs to the navy.
      [1913 Webster]

   4. same as navy blue.
      [PJC]

   Navy bean. see Bean.

   Navy yard, a place set apart as a shore station for the use
      of the navy. It often contains all the mechanical and
      other appliences for building and equipping war vessels
      and training their crews.
      [1913 Webster]