Relating to a large opening, aperture, or perforation: "A hiatal hernia is an anatomical abnormality in which part of the stomach protrudes through a diaphragm (large muscle between the lungs and the stomach that helps people to breathe) and up into the chest."

The protrusion of the stomach up into the opening that is normally occupied by the esophagus in the diaphragm, which is the muscle that separates the chest cavity from the abdomen.

A hiatal hernia can be congenital or it can be acquired through strenuous physical activity and it may contribute to gastroesophageal reflux disease with associated symptoms.