diencephalon

from WordNet (r) 3.0 (2006)

diencephalon
    n 1: the posterior division of the forebrain; connects the
         cerebral hemispheres with the mesencephalon [syn:
         {diencephalon}, {interbrain}, {betweenbrain},
         {thalmencephalon}]

from The Collaborative International Dictionary of English v.0.48

Diencephalon \Di`en*ceph"a*lon\, n. [NL. See {Dia-}, and
   {Encephalon}.] (Anat.)
   The interbrain or thalamencephalon; -- sometimes abbreviated
   to dien. See {Thalamencephalon}.
   [1913 Webster]

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