17 surnames on this site, with what each one means.
O'BrienParent’s name · rank 261Irish patronymic surname meaning “descendant of Brian,” from Ó Briain.
O'ConnellParent’s name · rank 986An Irish surname from Gaelic Ó Conaill, “descendant of Conall,” a personal name from elements for “hound/wolf” and “valour.”
O'ConnorParent’s name · rank 416Descendant of Conchobhar, the Irish personal name behind Connor.
O'DonnellParent’s name · rank 784An Irish surname from Gaelic Ó Domhnaill, “descendant of Domhnall,” a personal name often glossed as “world-mighty.”
O'NealParent’s name · rank 733An Irish patronymic surname from Ó Néill, meaning “descendant of Niall.”
O'NeillParent’s name · rank 673An Irish surname, anglicized from Ó Néill or Ua Néill, meaning “descendant of Niall.”
OchoaParent’s name · rank 408From Otxoa/Otsoa, a Basque personal name meaning “the wolf.”
OliverParent’s name · rank 278A surname from the medieval personal name Oliver, with English, French, and Scandinavian naming histories.
OlsenParent’s name · rank 571A Scandinavian patronymic meaning “son of Ole or Olaf.”
OlsonParent’s name · rank 166A Scandinavian patronymic meaning “son of Ole or Olaf,” from the suffix -son.
OrozcoPlace · rank 500A Basque habitational surname from Orozko in Biscay, formed from the name of a locality in the Basque Country.
OrrNickname · rank 795A Scottish and Ulster surname from Gaelic odhar, “dun” or “sallow,” with a separate English route from Old Norse Orri, “black grouse.”
OrtegaPlace · rank 243Spanish habitational or topographic surname associated with Ortega places; some analyses connect the place name with ortiga, “nettle.”
OrtizParent’s name · rank 68Son of Orti — Spanish patronymic; Orti from Basque/Latin Fortunius (“fortunate”).
OsborneParent’s name · rank 513A surname from the personal name Osbern, derived from Old Norse elements meaning “god” and “bear.”
OwenParent’s name · rank 561A Welsh and English surname from the personal name Owen, often a patronymic meaning “son or descendant of Owen.”
OwensParent’s name · rank 143A patronymic surname meaning “son of Owen,” with additional Irish Mac Eoghain forms.