Wiktionary
n. (surname A=An Irish patronymic from=Irish dot=) from Reilly.
Wikipedia
O'Reilly is a group of families, ultimately all of Irish Gaelic origin, who were historically the kings of East Bréifne in what is today County Cavan. The clan were part of the Connachta's Uí Briúin Bréifne kindred and were closely related to the Ó Ruairc (O'Rourkes) of West Bréifne. O'Reilly is ranked tenth in the top twenty list of Irish surnames.
It is also the patronymic form of the Irish name Reilly ( Irish Gaelic: Uí Raghaile). It is commonly found throughout Ireland, with the greatest concentration of the surname found in County Cavan followed by Longford, Meath, Westmeath, Fermanagh and Monaghan, and the Province of Leinster.
O'Reilly is a surname of Irish origin.
O'Reilly may also refer to:
Usage examples of "o'reilly".
Soy Luke d'S6raphin, y esta es mi amiga, Sefiorita CaseyM eolmtmee OAW-Atlwely O'Reilly.
An 'Aredy lookin' like a righteous plaster saint, an' O'Reilly like th' cat in th' cream!
I don't know about the officers, but Sergeant Major Noonan will come, and that fellow Rourke, and there's a wild bugger called Leon O'Reilly who wants nothing more than to kill Crapauds and there's plenty more like him.
Then, with a glance at O'Reilly and a nod to her dressers, Maya went to work.
He died when I was two, so I never really knew him, but he gave me my surname, which is O'Reilly, and I always had dual nationality.
Gwydion had had no unearthly visitor in the night, nor had he had any sleep either, but instead had spent all his time in the marana trance, fashioning what he prayed to every god that ever was would be escape for him and O'Reilly.
O'Reilly is anti-death penalty and pro-gun control, believes in "global warming," and thought Elian Gonzalez should go back to Cuba— not positions generally associated with the Republican Party.