stomach: an enlarged and muscular saclike organ of the alimentary canal; the principal organ of digestion
In vertebrates such as mammals the abdomen (belly) constitutes the part of the body between the thorax (chest) and pelvis. The region enclosed by the abdomen is termed the abdominal cavity. In arthropods it is the most distal section of the body which lies behind the thorax or cephalothorax.
stomach; (slang) A protruding belly; a paunch
the frontal area located between the ribs and the pubis. Surgery of the abdomen is frequently either by liposuction or by lift.