archencephalon: Meaning and Definition of

arch•en•ceph•a•lon

Pronunciation: (är"ken-sef'u-lon"), [key]
— n. Embryol.
  1. the primitive forebrain region of the embryo, anterior to the notochord, that gives rise to the midbrain and forebrain.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.