girder definition

1. One who, or that which, girds.

2. 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. Bowstring girder, Box girder, etc. See Bowstring, Box, etc. Girder bridge. See 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. Sandwich girder, a girder consisting of two parallel wooden beams, between which is an iron plate, the whole clamped together by iron bolts.

Origin: From Gird to encircle.