glacier vs ice floe

glacier

noun
  • A large body of ice which flows under its own mass, usually downhill. 

ice floe

noun
  • An ice stream (ice flow), a type of fast moving glacier 

  • An ice dam (ice jam), a blockage of ice in a river starting with an ice floe in the river. 

  • Any type of sea ice not attached to land, drift ice. 

  • A flat mass of floating ice, smaller than an ice field. 

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