A long fold of peritoneal membrane (see PERITONEUM), loaded with fat, which hangs down within the cavity of the ABDOMEN in front of the bowels. It is formed by the layers of peritoneum that cover the front and back surfaces of the stomach and extend from the lower margin of this organ to cover the back and front surfaces of the large intestine. Instead of passing straight from one organ to the other, these layers dip down and form a fourfold apron. This omentum is known as the greater omentum, to distinguish it from two smaller peritoneal folds, one of which passes between the liver and stomach (the hepatogastric omentum), and the other between the liver and duodenum (the hepato-duodenal omentum). Together these are known as the lesser omentum.