Myelencephalon \My`e*len*ceph"a*lon\, n. [NL., from Gr. myelo`s
marrow + E. encephalon.] (Anat.)
(a) The brain and spinal cord; the cerebro-spinal axis.
Sometimes abbreviated to {myelencephal}.
(b) The metencephalon. --Huxley.
[1913 Webster]