Which term means 'hollow shaft' in German?

The term that means 'hollow shaft' in German is indeed "Hohlwelle." In this context, "Hohl" translates to "hollow," and "Welle" translates to "shaft" or "wave." This compound word specifically refers to a shaft that is not solid but rather has a hollow interior, which is often used in engineering and mechanical contexts.

The other terms do not encapsulate the same meaning. "Rohr" typically refers to a tube or pipe, which implies a hollow structure but doesn't convey the specific concept of a shaft. "Stab" translates to "rod," which suggests a solid shape rather than a hollow one. "Pylon" refers to a type of tower or structure, different from the idea of a hollow shaft. Thus, "Hohlwelle" correctly conveys the intended meaning.