arc vs half-moon

arc

noun
  • That part of a circle which a heavenly body appears to pass through as it moves above and below the horizon. 

  • A directed edge. 

  • An arclight. 

  • A story arc. 

  • A continuous part of the circumference of a circle (circular arc) or of another curve. 

  • A curve, in general. 

  • A continuous mapping from a real interval (typically [0, 1]) into a space. 

  • A flow of current across an insulating medium; especially a hot, luminous discharge between either two electrodes or as lightning. 

  • A band contained within parallel curves, or something of that shape. 

  • The three-point line. 

verb
  • To shape into an arc; to hold in the form of an arc. 

  • To form an electrical arc. 

  • To move following a curved path. 

half-moon

noun
  • The moon in its first or last quarter when only half the visible face is illuminated; a quarter moon. 

  • A semicircular or crescent-shaped Filipino butter cookie. 

  • Anything shaped like a crescent, especially the base of a fingernail. 

  • Synonym of black and white (“type of cookie”) 

How often have the words arc and half-moon occurred in a corpus of books? (source: Google Ngram Viewer )