The term 'Zeppelin, e.g.' is a reference to a type of AIRSHIP, which is a large aircraft that is filled with a gas lighter than air, such as hydrogen or helium, and is held up by the buoyancy of the gas. Zeppelins are named after Count Ferdinand von Zeppelin, who designed the first rigid AIRSHIP in the late 19th century. They were used for both commercial and military purposes, and were popular until the 1930s when they were replaced by airplanes.