from The American Heritage® Dictionary of the English Language, 4th Edition
- n. The portion of the vertebrate brain that develops from the middle section of the embryonic brain.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A part of the brain located rostral to the pons and caudal to the thalamus and the basal ganglia, composed of the tectum (dorsal portion) and the tegmentum (ventral portion).
from the GNU version of the Collaborative International Dictionary of English
- n. The middle segment of the brain; the mesencephalon. See brain.
from The Century Dictionary and Cyclopedia
- n. The mesencephalon. See cuts under encephalon.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. the middle portion of the brain
mid- + brain (Wiktionary)