n. A bed consisting of a bag filled with straw, hair, moss, sponge, husks, excelsior, or other soft and elastic material, and usually quilted or tacked with transverse cords at short intervals to prevent the contents from slipping.n. In hydraulic engineering, a mat or mass of brushwood, willow rods, light poles, or other like material, roughly woven or tied together and used to form foundations for dikes and jetties, or as aprons, fencing, curtains, or surfacing for dikes, dams, embankments, and similar constructions, either for assisting to hold together loose material or to prevent injury by the erosion of water.