Which term refers to a 'pulley' in German?

The term that refers to a 'pulley' in German is indeed "Flaschenzug." In German, "Flaschenzug" specifically describes a system of pulleys used to lift heavy objects, which is consistent with the mechanical function of a pulley. This term captures the idea of both the pulley itself and the accompanying system that facilitates lifting through the mechanical advantage provided by the arrangement of pulleys.

The other terms listed do not relate to the concept of a pulley. "Schicht" translates to "layer," which does not convey any mechanical meaning. "Hohlwelle" means "hollow shaft," referring to a different component in machinery that is structurally different from a pulley. "Stab" translates to "rod" or "stick," which again has no direct relevance to the function or definition of a pulley. Thus, "Flaschenzug" is the accurate and contextually correct answer for the term describing a pulley in German.