concave vs crescent

concave

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

  • 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. 

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

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. 

crescent

adj
  • Shaped like a crescent. 

verb
  • To form a crescent shape 

  • To decorate with crescents. 

noun
  • A curved street, often presenting a continuous façade, as of row houses. 

  • A representation of crescent used as a symbol of Islam. 

  • The emblem of the waxing Moon with horns directed upward, when used in a coat of arms; often used as a mark of cadency to distinguish a second son and his descendants. 

  • The figure of the moon as it appears between its first or last quarter and the new moon, with concave and convex edges terminating in points. 

  • A curved pastry. 

  • A crescent spanner. 

  • Any of three orders of knighthood conferred upon foreigners to whom Turkey might be indebted for valuable services. 

  • A crescentspot butterfly. 

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