stomach

1a (1) :  a saclike expansion of the digestive tract of a vertebrate that is located between the esophagus and duodenum and typically consists of a simple often curved sac with an outer serous covering, a strong muscular wall that contracts rhythmically, and an inner mucous membrane lining that contains gastric glands ◆In humans, the stomach is located in the upper abdomen, below the esophagus and above the small intestine . It functions mainly to partially digest food by grinding and mixing it with gastric secretions (such as hydrochloric acid and pepsin). Mucus is also secreted to protect the stomach lining from damage by the acidic environment. Once ingested food has been partially digested by the stomach, it is discharged through the pylorus into the duodenum in the form of the semifluid chyme for further digestion. (2) :  one of the compartments making up the stomach of a ruminant animal (such as a cow or sheep) … the rumen, the largest of the four stomachs in an older animal, is undeveloped at birth and is considerably smaller than the abomasum or true stomach. — Norman Barronb :  a cavity in an invertebrate animal that is analogous to a stomach When a leaf containing the bacteria is ingested by the larva of certain insects, the new gene produces a protein that attacks the stomach lining of the insect and causes death. — The New York Timesc :  the part of the body that contains the stomach :  belly, abdomen He was punched in the stomach.

2a :  desire for food caused by hunger :  appetite After the hke, she had a good stomach for lunch.b :  inclination, desire had no stomach for an argument; also :  courage, guts

3 obsolete a :  spirit, valorb :  pridec :  spleen, resentment