Both blimps and rigids are dirigible (able to be steered and controlled) and both are airships. Blimps are like balloons, the inflation pressure gives them their form. Some people call rigid airships Zeppelins, but that is that figure of speech-forget what it is called- that turns a brand name into a general description, like aspirin. I think the best name for rigids is rigid airship. Be nice if there was a general term for them, but I don't think there is. BTW, one of the big ongoing arguments in lighter-than-air is the origin of the term "blimp."
Another interesting thing- Atlas missiles and launchers, at least the earlier ones, relied on fuel and oxidizer pressure to keep their shape. The skin was so thin the weight of the payload would collapse the structure if the pressure failed. So can we call an Atlas a blimp?