n. An aircraft, such as a dirigible or balloon, that derives its lift from buoyancy rather than from wings or rotors.
n. A moored balloon flown in a semi-permanent manner, as a border patrol monitoring balloon affixed at 18,000 feet (~6km).
Word Usage
"AFP/Getty Images Then: The aerostat is illuminated in green during the Commonwealth Games opening ceremony at the Jawaharlal Nehru stadium in New Delhi, October 3, 2010."