girder

n. [ From Gird to encircle. ] [ 1913 Webster ]

1. One who, or that which, girds. [ 1913 Webster ]

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. [ 1913 Webster ]

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. [ 1913 Webster ]