The name Petronilla is a girl's name of Italian, Latin origin meaning "yokel". Petronilla and is often added to lists like Badass Princess Names and discussed in our forums with posts like "Quick Question Thread?!".
From the experts:
Petronilla is an ancient saint's name that relates to the Roman family name Petronius, thought to mean yokel, though some connect it with Petra or Peter, meaning stone. With the resurgence of so many ancient Roman names, the elaborate and pretty Petronilla or its French form Petronille seem more usable these days than they have in centuries.