Girder \Gird"er\, n. [From Gird to encircle.]
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   1. One who, or that which, girds.
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   2. (Arch. & Engin.) A main beam; a stright, horizontal beam
      to span an opening or carry weight, such as ends of floor
      beams, etc.; hence, a framed or built-up member
      discharging the same office, technically called a compound
      girder. See Illusts. of Frame, and Doubleframed floor,
      under Double.
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   Bowstring girder, Box girder, etc. See under Bowstring,
      Box, etc.

   Girder bridge. See under Bridge.

   Lattice girder, a girder consisting of longitudinal bars
      united by diagonal crossing bars.

   Half-lattice girder, a girder consisting of horizontal
      upper and lower bars connected by a series of diagonal
      bars sloping alternately in opposite directions so as to
      divide the space between the bars into a series of
      triangles. --Knight.

   Sandwich girder, a girder consisting of two parallel wooden
      beams, between which is an iron plate, the whole clamped
      together by iron bolts.
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Bridge \Bridge\ (br[i^]j), n. [OE. brig, brigge, brug, brugge,
   AS. brycg, bricg; akin to Fries. bregge, D. brug, OHG.
   brucca, G. br["u]cke, Icel. bryggja pier, bridge, Sw. brygga,
   Dan. brygge, and prob. Icel. br[=u] bridge, Sw. & Dan. bro
   bridge, pavement, and possibly to E. brow.]
   1. A structure, usually of wood, stone, brick, or iron,
      erected over a river or other water course, or over a
      chasm, railroad, etc., to make a passageway from one bank
      to the other.
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   2. Anything supported at the ends, which serves to keep some
      other thing from resting upon the object spanned, as in
      engraving, watchmaking, etc., or which forms a platform or
      staging over which something passes or is conveyed.
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   3. (Mus.) The small arch or bar at right angles to the
      strings of a violin, guitar, etc., serving of raise them
      and transmit their vibrations to the body of the
      instrument.
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   4. (Elec.) A device to measure the resistance of a wire or
      other conductor forming part of an electric circuit.
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   5. A low wall or vertical partition in the fire chamber of a
      furnace, for deflecting flame, etc.; -- usually called a
      bridge wall.
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   Aqueduct bridge. See Aqueduct.

   Asses' bridge, Bascule bridge, Bateau bridge. See under
      Ass, Bascule, Bateau.

   Bridge of a steamer (Naut.), a narrow platform across the
      deck, above the rail, for the convenience of the officer
      in charge of the ship; in paddlewheel vessels it connects
      the paddle boxes.

   Bridge of the nose, the upper, bony part of the nose.

   Cantalever bridge. See under Cantalever.

   Draw bridge. See Drawbridge.

   Flying bridge, a temporary bridge suspended or floating, as
      for the passage of armies; also, a floating structure
      connected by a cable with an anchor or pier up stream, and
      made to pass from bank to bank by the action of the
      current or other means.

   Girder bridge or Truss bridge, a bridge formed by
      girders, or by trusses resting upon abutments or piers.

   Lattice bridge, a bridge formed by lattice girders.

   Pontoon bridge, Ponton bridge. See under Pontoon.

   Skew bridge, a bridge built obliquely from bank to bank, as
      sometimes required in railway engineering.

   Suspension bridge. See under Suspension.

   Trestle bridge, a bridge formed of a series of short,
      simple girders resting on trestles.

   Tubular bridge, a bridge in the form of a hollow trunk or
      rectangular tube, with cellular walls made of iron plates
      riveted together, as the Britannia bridge over the Menai
      Strait, and the Victoria bridge at Montreal.

   Wheatstone's bridge (Elec.), a device for the measurement
      of resistances, so called because the balance between the
      resistances to be measured is indicated by the absence of
      a current in a certain wire forming a bridge or connection
      between two points of the apparatus; -- invented by Sir
      Charles Wheatstone.
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