the bilge or protuberant part of a cask.-a swelling, protuberant part; a bending outward, esp. when caused by pressure; as, a bulge in a wall.-the bilge of a vessel. see bilge, 2.-to swell or jut out; to bend outward, as a wall when it yields to pressure; to be protuberant; as, the wall bulges.-to bilge, as a ship; to founder.