convexity vs vacuity

convexity

noun
  • The state of being convex. 

  • A convex line or surface. 

  • A measure of the curvature in the relationship between the prices and yields of bonds. 

vacuity

noun
  • Idleness; listlessness. 

  • Emptiness. 

  • Physical emptiness, an absence of matter; vacuum. 

  • An empty or inane remark or thing. 

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