Any girl who is aroused by the sound or appearance of a diesel truck. Whether a Duramax, Powerstroke, or Cummins, these ladies can't get enough of diesel. They often are willing to perform certain "favors" to the men who own these diesel trucks in order to ride in one of these jacked-up, beautiful machines. Until they get what they want (a diesel truck of their own, one to spend all of their time with), they will continue to do whatever it takes to get a diesel fix.

Literally everyone, ever. Including the writer of this definition.