Wordnet 3.0
NOUN (1)
1.
the posterior part of the hindbrain in developing vertebrates;
forms the medulla oblongata in adults;
The Collaborative International Dictionary of English v.0.48:
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]
WordNet (r) 3.0 (2006):
myelencephalon
n 1: the posterior part of the hindbrain in developing
vertebrates; forms the medulla oblongata in adults