balloon'-sick'ness

i Pain in the back of the head and neck, dimne of vision, drowsine , dyspnea, and a sense of extreme fatigue, occurring in aeronauts on reaching a height of 10,000 to 15,000 feet; a condition similar to mountain sickne and caused by the rarity of the atmosphere. 2. A condition similar to seasickne occurring at low altitudes, due to the swaying and irregular motion of the car.