Source : Webster's Revised Unabridged Dictionary (1913)

Rail \Rail\, n. [Akin to LG. & Sw. regel bar, bolt, G. riegel a
   rail, bar, or bolt, OHG, rigil, rigel, bar, bolt, and
   possibly to E. row a line.]
   1. A bar of timber or metal, usually horizontal or nearly so,
      extending from one post or support to another, as in
      fences, balustrades, staircases, etc.

   2. (Arch.) A horizontal piece in a frame or paneling. See
      Illust. of {Style}.

   3. (Railroad) A bar of steel or iron, forming part of the
      track on which the wheels roll. It is usually shaped with
      reference to vertical strength, and is held in place by
      chairs, splices, etc.

   4. (Naut.)
      (a) The stout, narrow plank that forms the top of the
          bulwarks.
      (b) The light, fencelike structures of wood or metal at
          the break of the deck, and elsewhere where such
          protection is needed.

   {Rail fence}. See under {Fence}.

   {Rail guard}.
      (a) A device attached to the front of a locomotive on each
          side for clearing the rail obstructions.
      (b) A guard rail. See under {Guard}.

   {Rail joint} (Railroad), a splice connecting the adjacent
      ends of rails, in distinction from a chair, which is
      merely a seat. The two devices are sometimes united. Among
      several hundred varieties, the fish joint is standard. See
      {Fish joint}, under {Fish}.

   {Rail train} (Iron & Steel Manuf.), a train of rolls in a
      rolling mill, for making rails for railroads from blooms
      or billets.