The Collaborative International Dictionary of English v.0.48:

Herrenvolk \Her"ren*volk\ (h[e^]r"ren*f[=o]lk`), n. [German.]
   a race that considers itself superior to all others and
   fitted to rule the others; -- referred to especially in NAZI
   racial theories.

   Syn: master race.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

Herrenvolk
    n 1: a race that considers itself superior to all others and
         fitted to rule the others [syn: master race,
         Herrenvolk]