Meanings
proper noun
- A surname from Irish.
Origin
- IrishÓ Súilleabháin
- EnglishO'Sullivan
From Irish Ó Súilleabháin.
More words from Irish
Full word history & related roots →Cite this entry
APA
O'Sullivan. (n.d.). In WatkinsX Dictionary. Retrieved November 4, 2026, from https://dictionary.watkinsx.com/word/O'Sullivan
MLA
“O'Sullivan.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/O'Sullivan. Accessed November 4, 2026.
Chicago
WatkinsX Dictionary, s.v. “O'Sullivan,” accessed November 4, 2026, https://dictionary.watkinsx.com/word/O'Sullivan.
Source: O'Sullivan on Wiktionary, CC BY-SA 4.0.