Today it means: A dog of a medium to large, predominantly white breed with short, coarse coat, squarish flat skull, and powerful jaws and hind legs, originally bred as a protection and defense dog against the hostile frontier of early Spanish Florida. They are the closest descendants of the old Spanish guard and war dogs brought by settlers and conquistadors to Argentina and Spanish Florida. Full definition →
English, from English Butcher's Alaunt, a name given the breed by early English settlers in southern Georgia in reference to the old Butcher's Alaunt of England, a predominantly white dog of similar type and function.
Etymology from Wiktionary, CC BY-SA 4.0.