About the O'Leary surname
The surname O'Leary is associated with a patronymic formation. The O' particle is an old Irish patronymic formation associated with descent. A patronymic formation of this kind shows how an older personal name could develop into a family name. The O’ particle in O'Leary is characteristic of many Irish surnames and traditionally refers to descent. In the normalization used for some LAFRANCE searches, the surname is also matched through the form “oleary”; this search variant can be useful when accents, spaces, or punctuation differ.
Pronunciation:
Eou-li-ri/əʊliʁi/