D defs.my
Entry 1 sense Webster, 1913

Mesencephalon

· Mes·en·ceph·a·lon · IPA /ˌmɛzənˈsɛfələn/
01 n. The middle segment of the brain; the midbrain. Sometimes abbreviated to mesen. See Brain.
  1. 1.
    The middle segment of the brain; the midbrain. Sometimes abbreviated to mesen. See Brain.(Anat.) Also: mesen See: Brain