The Collaborative International Dictionary
Sphenethmoid bone
Sphenethmoid \Sphe*neth"moid\, a. [Sphenoid + ethmoid.] (Anat.) Of or pertaining to both the sphenoidal and the ethmoidal regions of the skull, or the sphenethmoid bone; sphenethmoidal.
Sphenethmoid bone (Anat.), a bone of the skull which surrounds the anterior end of the brain in many amphibia; the girdle bone.