concave vs prominent

concave

verb
  • To render concave, or increase the degree of concavity. 

adj
  • Hollow; empty. 

  • Satisfying the property that all segments connecting two points on the function's graph lie below the function. 

  • Not convex; having at least one internal angle greater than 180 degrees. 

  • Curved like the inner surface of a sphere or bowl. 

noun
  • A playing card made concave for use in cheating. 

  • One of the celestial spheres of the Ptolemaic or geocentric model of the world. 

  • An indentation running along the base of a surfboard, intended to increase lift. 

  • An element of a curved grid used to separate desirable material from tailings or chaff in mining and harvesting. 

  • The vault of the sky. 

  • An indented area on the top of a skateboard, providing a position for foot placement and increasing board strength. 

  • A concave surface or curve. 

prominent

noun
  • Any of various moths having a conspicuous projection on the inner margin of the wings. 

  • In Nazi concentration camps, an inmate entrusted with minor supervisory duties and rewarded with perquisites. 

adj
  • standing out, or projecting; jutting; protuberant 

  • likely to attract attention from its size or position; conspicuous 

  • eminent; distinguished above others 

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