chassis vs mudguard

chassis

noun
  • The base frame of a motor vehicle. 

  • A woman's buttocks. 

  • A base frame, or movable railway, along which the carriage of a mounted gun moves backward and forward. 

  • A frame or housing containing electrical or mechanical equipment, such as on a computer. 

mudguard

noun
  • A cover over the wheels of a vehicle, or a flap behind that wheel, to prevent water and mud being projected. 

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