A Zeppelin is a type of AIRSHIP, which is a type of aircraft that is lighter than air and propelled by engines. It was invented by Count Ferdinand von Zeppelin in the late 19th century. The term Zeppelin is often used interchangeably with AIRSHIP, BALLOON, BLIMP, and dirigible, but technically it refers to a specific type of rigid AIRSHIP developed by Graf Ferdinand von Zeppelin. It is characterized by a cylindrical shape, an internal metal frame, and a propulsion system that uses multiple propellers powered by internal combustion engines.