hibernal vs icebox

hibernal

adj
  • Of or pertaining to winter; brumal or hiemal 

icebox

adj
  • agreeable, awesome. (as a superlative of cool) 

noun
  • A box or compartment containing ice, typically used to keep provisions cool. 

  • A compartment in a refrigerator that is colder than the rest of the refrigerator and is used as a freezer. 

  • A prison. 

  • A morgue. 

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