2.AdjectiveOf or relating to the sphenoid bone which forms the base of the cranium, behind the eye and below the front part of the brain. It has two pairs of broad lateral ‘wings’ and a number of other projections, and contains two air-filled sinuses.
3.NounThe sphenoid bone.
4.NounA wedge-shaped crystal bounded by four equal isosceles triangles; the hemihedral form of a square pyramid.