Any belly condition with severe pain as a result of inflammation, perforation, obstruction, or injury of the stomach area: A medical term for the quick onset of abdominal pain, a potential medical emergency due to an acute abdomen, may reflect a major problem with one of the organs in the abdomen, such as appendicitis (inflamed appendix), cholecystitis (inflamed gallbladder), a perforated ulcer in the intestine, or a ruptured spleen, which is located on the left side of the abdomen near the stomach, filters blood, and serves as a major reservoir for blood.