Terrone literally means someone who works on the land (i.e. farmer). Adopted as a derogatory term, it was used by the pompous people of the Friuli region against any Italian from Rome southwards. "Terroni" are the salt of Italy´s earth. They are the people who give Italians a good name abroad. "Terroni" (southern Italian immigrants) helped build New York and fought for the U.S. war efforts in WW2.
"Terroni" are the ones who brought the Vera Pizza Napoletana in the world.