What does "apron" mean?

Apron: Something which by its shape or use suggests an apron; as, (a) The fat skin covering the belly of a goose or duck. [Prov. Eng.] Halliwell. (b) A piece of leather, or other material, to be spread before a person riding on an outside seat of a vehicle, to defend him from the rain, snow, or dust; a boot. "The weather being too hot for the apron." Hughes. (c) (Gun.) A leaden plate that covers the vent of a cannon. (d) (Shipbuilding) A piece of carved timber, just above the foremost end of the keel. Totten. (e) A platform, or flooring of plank, at the entrance of a dock, against which the dock gates are shut. (f) A flooring of plank before a dam to cause the water to make a gradual descent. (g) (Mech.) The piece that holds the cutting tool of a planer. (h) (Plumbing) A strip of lead which leads the drip of a wall into a gutter; a flashing. (i) (Zoöl.) The infolded abdomen of a crab.