prop shaft vs propeller shaft

prop shaft

noun
  • propeller shaft; driveshaft. 

propeller shaft

noun
  • The shaft which transmits the rotary motion from an engine to a propeller, as on a ship or aircraft. 

  • the shaft which connects the gearbox to the differential on the axle of a rear-wheel-drive or four-wheel-drive vehicle. 

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