Giordano's sign refers to a physical examination maneuver used to assess for the presence of peritoneal inflammation or irritation. It involves applying pressure to the lower abdomen with the hand and fingers, and then quickly releasing it. If the maneuver elicits pain or tenderness upon release, it is considered positive for Giordano's sign, indicating potential peritoneal inflammation. This sign can be useful in evaluating patients with suspected peritonitis or other intra-abdominal conditions.