medicommissure

from The Collaborative International Dictionary of English v.0.48

Medicommissure \Med`i*com"mis*sure\, n. [L. medius middle + E.
   commissure.] (Anat.)
   A large transverse commissure in the third ventricle of the
   brain; the middle or soft commissure. --B. G. Wildex.
   [1913 Webster]