half-moon vs lunula

half-moon

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

  • A semicircular or crescent-shaped Filipino butter cookie. 

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

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

lunula

noun
  • Something shaped like a crescent or half-moon; especially the pale area at the base of the fingernail. 

  • A crescent moon-shaped pendant worn by girls in Ancient Rome. 

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