The Collaborative International Dictionary of English v.0.48:

Floor \Floor\ (fl[=o]r), n. [AS. fl[=o]r; akin to D. vloer, G.
   flur field, floor, entrance hall, Icel. fl[=o]r floor of a
   cow stall, cf. Ir. & Gael. lar floor, ground, earth, W.
   llawr, perh. akin to L. planus level. Cf. Plain smooth.]
   1. The bottom or lower part of any room; the part upon which
      we stand and upon which the movables in the room are
      supported.
      [1913 Webster]

   2. The structure formed of beams, girders, etc., with proper
      covering, which divides a building horizontally into
      stories. Floor in sense 1 is, then, the upper surface of
      floor in sense 2.
      [1913 Webster]

   3. The surface, or the platform, of a structure on which we
      walk or travel; as, the floor of a bridge.
      [1913 Webster]

   4. A story of a building. See Story.
      [1913 Webster]

   5. (Legislative Assemblies)
      (a) The part of the house assigned to the members.
      (b) The right to speak; as, the gentleman from Iowa has
          the floor. [U.S.]
          [1913 Webster]

   Note: Instead of he has the floor, the English say, he is in
         possession of the house.
         [1913 Webster]

   6. (Naut.) That part of the bottom of a vessel on each side
      of the keelson which is most nearly horizontal.
      [1913 Webster]

   7. (Mining)
      (a) The rock underlying a stratified or nearly horizontal
          deposit.
      (b) A horizontal, flat ore body. --Raymond.
          [1913 Webster]

   Floor cloth, a heavy fabric, painted, varnished, or
      saturated, with waterproof material, for covering floors;
      oilcloth.

   Floor cramp, an implement for tightening the seams of floor
      boards before nailing them in position.

   Floor light, a frame with glass panes in a floor.

   Floor plan.
      (a) (Shipbuilding) A longitudinal section, showing a ship
          as divided at the water line.
      (b) (Arch.) A horizontal section, showing the thickness of
          the walls and partitions, arrangement of passages,
          apartments, and openings at the level of any floor of
          a house.
          [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Plan \Plan\, n. [F., fr. L. planus flat, level. See Plain, a.]
   1. A draught or form; properly, a representation drawn on a
      plane, as a map or a chart; especially, a top view, as of
      a machine, or the representation or delineation of a
      horizontal section of anything, as of a building; a
      graphic representation; a diagram.
      [1913 Webster]

   2. A scheme devised; a method of action or procedure
      expressed or described in language; a project; as, the
      plan of a constitution; the plan of an expedition.
      [1913 Webster]

            God's plans like lines pure and white unfold. --M.
                                                  R. Smith.
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   3. A method; a way of procedure; a custom.
      [1913 Webster]

            The simple plan,
            That they should take who have the power,
            And they should keep who can.         --Wordsworth.
      [1913 Webster]

   Body plan, Floor plan, etc. See under Body, Floor,
      etc.
      [1913 Webster]

   Syn: Scheme; draught; delineation; plot; sketch; project;
        design; contrivance; device. See Scheme.
        [1913 Webster]

WordNet (r) 3.0 (2006):

floor plan
    n 1: scale drawing of a horizontal section through a building at
         a given level; contrasts with elevation