BILGE, the widest part or "belly" of a cask; the broad horizontal part of a ship's bottom above the keel; also the lowest interior part of the hull; hence, "bilge-water," the foul water which collects in the bilge. "Bilge-keels" are pieces of timber fastened to the bottom of a ship to reduce rolling. The word is a corruption of bulge, from Fr. bouge, Lat. bulga, a bag, probably deriving from an original Celtic word.