blue moon vs geezerdom

blue moon

noun
  • A long time. 

  • The third full moon in a season that contains four rather than the usual three full moons. 

  • The second of two full moons that occur in the same calendar month (a definition created by mistake in the 20th century). 

  • A bright blue, sweet-flavored ice cream that is popular in the Midwestern U.S. and is a component of Superman ice cream. 

  • The moon tinted towards blue as it appears in the sky, caused by dust or smoke in the atmosphere. 

geezerdom

noun
  • old age 

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