Lattice girder

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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Lattice \Lat"tice\, n. [OE. latis, F. lattis lathwork, fr. latte
   lath. See {Latten}, 1st {Lath}.]
   1. Any work of wood, metal, plastic, or other solid material,
      made by crossing a series of parallel laths, or thin
      strips, with another series at a diagonal angle, and
      forming a network with openings between the strips; as,
      the lattice of a window; -- called also {latticework}.
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            The mother of Sisera looked out at a window, and
            cried through the lattice.            --Judg. v. 28.
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   2. (Her.) The representation of a piece of latticework used
      as a bearing, the bands being vertical and horizontal.
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   3. (Crystallography) The arrangement of atoms or molecules in
      a crystal, represented as a repeating arrangement of
      points in space, each point representing the location of
      an atom or molecule; called also {crystal lattice} and
      {space lattice}.
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   {Lattice bridge}, a bridge supported by lattice girders, or
      latticework trusses.

   {Lattice girder} (Arch.), a girder of which the wed consists
      of diagonal pieces crossing each other in the manner of
      latticework.

   {Lattice plant} (Bot.), an aquatic plant of Madagascar
      ({Ouvirandra fenestralis}), whose leaves have interstices
      between their ribs and cross veins, so as to resemble
      latticework. A second species is {Ouvirandra Berneriana}.
      The genus is merged in {Aponogeton} by recent authors.
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