Source : Webster's Revised Unabridged Dictionary (1913)

Rhinencephalon \Rhi`nen*ceph"a*lon\, n.; pl. {Rhinencephala}.
   [NL., fr. Gr. ???, ???, the nose + ?? the brain.] (Anat.)
   The division of the brain in front of the prosencephalon,
   consisting of the two olfactory lobes from which the
   olfactory nerves arise.

   Note: The term is sometimes used for one of the olfactory
         lobes, the plural being used for the two taken
         together.

Source : WordNet®

rhinencephalon
     n : a center in the cerebral hemispheres that governs the sense
         of smell in lower animals; in humans it seems to mediate
         complex emotional behavior [syn: {olfactory brain}]
     [also: {rhinencephala} (pl)]