Also reminds me of an interesting lesson we had in flying school, where our CFI was explaining that the "propeller" on an airplane should really be called a "tractor" because it is technically pulling the aircraft along, whereas an actual "propeller" would push the aircraft along (much as a ship's propeller does at the stern).
Sometimes talking about cars someone brings that up the other way around - rear wheels 'propel', the commonly used 'traction' is about the front wheels pulling the car ...
