Dirigible
A large, cigar-shaped, rigid, lighter-than-air flying machine. Dirigibles are made of a rigid truss structure covered with fabric. Gas bags inside the structure contain the lifting gas, which is either helium or hydrogen.
Aviation Maintenance Technician Handbook — Airframe, p. G-12
Also defined in 1 more source
A large, cigar shaped, lighter-than-air flying machine. Dirigibles differ from balloons in that they are powered and can be steered.
Aviation Maintenance Technician Handbook — Powerplant, p. G-9