south·ern·ism \ˈsəthə(r)ˌnizəm\noun (-s) Usage: usually capitalized 1.: a locution or pronunciation characteristic of the southern U.S. < can detect a phony southernism quicker than most theater men — Joshua Logan > 2.: an attitude or trait characteristic of the South or Southerners especially in the U.S. < his Southernisms had been thoroughly rubbed away — Robert Lowell >