The Collaborative International Dictionary of English v.0.48:

Alisphenoid \Al`i*sphe"noid\, Alisphenoidal \Al`i*sphe*noid"al\,
   a. [L. ala wing + E. sphenoid.] (Anat.)
   Pertaining to or forming the wing of the sphenoid; relating
   to a bone in the base of the skull, which in the adult is
   often consolidated with the sphenoid; as, alisphenoid bone;
   alisphenoid canal.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Alisphenoid \Al`i*sphe"noid\, n. (Anat.)
   The alisphenoid bone.
   [1913 Webster]