Dirigibles, Zeppelins, and Blimps:

What's the Difference?

According to Airships.com: A dirigible is any lighter-than-air craft that is both powered and steerable (as opposed to free floating, like a balloon). Blimps like the Goodyear blimp, rigid airships like the Hindenburg, and semi-rigid airships like the Zeppelin NT are all dirigibles.

A rigid airship has a framework surrounding one or more individual gas cells, and maintains its shape by virtue of its rigid framework and not the pressure of its lifting gas. A zeppelin is a rigid airship manufactured by a particular company, the Luftschiffbau Zeppelin of Germany (the "Zeppelin Airship Construction Company"), which was founded by Count Ferdinand von Zeppelin.

A blimp (technically called a "pressure airship") is a powered, steerable, lighter-than-air vehicle whose shape is maintained by the pressure of the gases within its envelope.

A blimp has no rigid internal structure; if a blimp deflates, it loses its shape. Blimps are best known today for their role as advertising and promotional vehicles. Goodyear began using blimps to advertise its brand in 1925 and The Lightship Group has operated promotional blimps for various companies over the past 20 years.

But blimps have also played an important role in the armed forces of many countries. For example, United States Navy's lighter-than-air program made extensive use of blimps from the 1920s through the 1950s, primarily in anti-submarine and reconnaissance roles.

A semi-rigid airship, like a blimp, maintains its aerodynamic shape from internal gas pressure, but it has a partial rigid frame, usually in the form of a keel, which supports

and distributes loads and provides structural integrity during maneuvering. The modern Zeppelin NT, such as the one currently carrying the Farmers Insurance logo, is a semi-rigid airship rather than a blimp.

Source: Airships.net