1. The large hollow space between the diaphragm and the groin: In the abdominopelvic cavity there is no structurally distinct separation between the abdomen and pelvic regions.

2. The largest hollow space of the body between the diaphragm and the top of the pelvic cavity and surrounded by the spine and the abdominal muscles and others: The abdominopelvic cavity contains most of the alimentary canal, the liver and pancreas, the spleen, the kidneys, and the adrenal glands. It is lined by the peritoneum, a membrane covering the cavity's inside wall, the parietal peritoneum, and each organ or structure in it, the visceral peritoneum.