If something has been moved upside down, it has been turned round so that the part that is usually lowest is above the part that is usually highest. The painting was hung upside down Salter held the bag by the corners and shook it upside down. Upside down is also an adjective. His eyes were open and everything he saw was upside down Tony had an upside-down map of Britain on his wall
to turn something upside down: see turn. in a position with the top at the bottom and the bottom at the top