Gírder. n.s. [from gird.] In architecture, the largest piece of timber in a floor. Its end is usually fastened into the summers, or breast summers, and the joints are framed in at one arm to the girders. Harris.
The girders are also to be of the same scantling the summers and ground-plates are of, though the back girder need not be so strong as the front girder. Moxon's Mech. Exer.
These mighty girders which the fabrick bind,
These ribs robust and vast in order join'd. Blackm. Creation.