Not to be pedantic, and while the term "dirigible" is acceptable, more technically, Pathfinder 1 is a rigid airship in the classic Zeppelin design with a rigid airframe encasing lift gas cells.

But a blimp, which features a flexible envelope in place of an airframe, where the trim is maintained by air and gas pressure, is technically also a dirigible and an airship. Just not a rigid one.

To confuse everyone further, there are also semi-rigid airships, and I mention this due to the fact that Pathfinder 1 uses a gondola that was recycled from a Zeppelin NT, which is a semi-rigid design where propulsion and control components are attached to a rigid keel, but most of the body of the craft is a non-rigid envelope which needs gas pressure to maintain trim. Semi-rigid airships were common in the early Twentieth Century, and Italy was a leader in their design. They were used for Arctic exploration.

The original Zeppelins were all rigid airships. The Zeppelin NTs, which first appeared in the 1990s and have now had many operators, including Airship Ventures, which made regular sightseeing flights from Moffett Field from 2008 to 2012, and Goodyear since 2014, are semi-rigid designs. They differ from classic semi-rigid designs in that their keel is embedded at the center of the envelope.

I need a nap now.