'Mesencephalon' definitions:

Definition of 'mesencephalon'

(from WordNet)
noun
The middle portion of the brain [syn: midbrain, mesencephalon]

Definition of 'Mesencephalon'

From: GCIDE
  • Mesencephalon \Mes`en*ceph"a*lon\, n. [NL. See Meso- and Encephalon.] (Anat.) The middle segment of the brain; the midbrain. Sometimes abbreviated to mesen. See Brain. [1913 Webster]