"Airplane" is now a household word. So is "airship." Careful households, capable of distinctions, use words correctly, do not confuse airplanes with airships. Aid is offered by the National Advisory Committee for Aeronautics Definitions:
Airplane: A mechanically driven aircraft, heavier-than-air, fitted with fixed wings.
Airship: An aerostat (lighter-than-air craft) with a propelling system.
Airship, nonrigid: An airship whose form is maintained by internal pressure in gas bags. . . .
Airship, rigid: Form maintained by a rigid structure.
Airship, semirigid: Form maintained by rigid or jointed keel, together with internal pressure.
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