glade vs ice cap

glade

noun
  • A bright surface of ice or snow. 

  • An everglade. 

  • An open passage through a wood; a grassy open or cleared space in a forest. 

  • An open space in the ice on a river or lake. 

ice cap

noun
  • A permanent expanse of ice encompassing a large geographical area, e.g. in Earth's polar zones or at high elevation. 

  • An ice pack designed to be worn on the head. 

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