hiatal hernia

:  herniation of an abdominal organ; specifically :  protrusion of part of the stomach upward into the chest cavity through the passage in the diaphragm for the esophagus that is typically accompanied with movement of the opening of the esophagus into the stomach to a position above the diaphragm and that may be asymptomatic or be accompanied by symptoms typical of gastroesophageal reflux (such as heartburn, belching, or bloating).