sphenoid vs tapered

sphenoid

adj
  • Having a wedged shape. 

  • Of 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. 

noun
  • A wedge-shaped crystal bounded by four equal isosceles triangles; the hemihedral form of a square pyramid. 

  • The sphenoid bone. 

tapered

adj
  • Narrowing gradually towards a point. 

How often have the words sphenoid and tapered occurred in a corpus of books? (source: Google Ngram Viewer )