Source : Webster's Revised Unabridged Dictionary (1913)

Hindbrain \Hind"brain`\, n. [Hind, adj. + brain.] (Anat.)
   The posterior of the three principal divisions of the brain,
   including the epencephalon and metencephalon. Sometimes
   restricted to the epencephalon only.

Source : WordNet®

hindbrain
     n : the posterior portion of the brain including cerebellum and
         brainstem [syn: {rhombencephalon}]