caravan vs wheel arch

caravan

noun
  • A furnished vehicle towed behind a car, etc., and used as a dwelling when stationary. 

  • A convoy or procession of travelers, their vehicles and cargo, and any pack animals, especially camels crossing a desert. 

verb
  • To travel in a caravan (procession). 

  • To travel and/or live in a caravan (vehicle). 

wheel arch

noun
  • The shaped part of the bodywork of a car or other vehicle that allows the wheel to be accessed, and in the case of front wheels, enable them to be steered. 

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