Gird·er, n.
  1. One who, or that which, girds.
  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.
  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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