gritter vs ski

gritter

noun
  • A vehicle that applies grit to icy roads to improve traction 

ski

noun
  • One of a pair of long flat runners designed for gliding over snow or water. 

  • One of a pair of long flat runners under some flying machines, used for landing. 

verb
  • To travel over (a slope, etc.) on skis; to travel on skis at (a place), (especially as a sport). 

  • To move on skis. 

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