Samheiti fyrir Petur í mismunandi löndum og tungumálum: Bedros, Botros, Boutros, Butrus, Peadar, Pece, Peder, Pedr, Pedrinho, Pedro, Péter, Peer, Peers, Peeter, Pétur, Pehr, Peio, Pèire, Pejo, Pekka, Pelle, Penko, Per, Pere, Perica, Perig, Pero, Peru, Petar, Pete, Peter, Petera, Peti, Petia, Petr, Petras, Petre, Petri, Petrica, Petro, Petros, Petru, Petruccio, Petrus, Petter, Petteri, Petya, Piaras, Pier, Pierino, Piero, Pierre, Pierrick, Piers, Piet, Pietari, Pieter, Pietro, Pika, Piotr, Pit, Pitter, Pyotr. Fá Petur á öðrum tungumálum.
Samheiti eftir Williamson í mismunandi löndum og tungumálum: Mac uileagóid, Macwilliam, Mcelligott, Mcwilliam, Willems, Willemse, Willemsen, Wilms. Fá Williamson á öðrum tungumálum.
Algengustu nöfnin með eftirnafninu Williamson: Cynthia, Claire, Tuesday, Carlo, Robert, Róbert. Fá Nöfn sem fara með Williamson.