{ Ba`si*sphe"noid (&?;), Ba`si*sphe*noid"al (&?;), } a. [Basi- + sphenoid.] (Anat.) Of or pertaining to that part of the base of the cranium between the basioccipital and the presphenoid, which usually ossifies separately in the embryo or in the young, and becomes a part of the sphenoid in the adult.