| Tully | Irish | Anglicized form of Tuathal (people .. |  |  |
| Turlough | Irish | Common Anglicized form of Toirdealb.. | | |
| Tynan | Irish | Meaning "dark." A popular nickname .. | | |
| Tyrone | Irish | Transferred use of a place-name in .. |  | |
| Uaine | Irish | See Owen.
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| Uaithne | Irish | Old name derived from uaithne (gree.. | | |
| Ualtar | Irish | Gaelic form of Walter (ruler of an .. | | |
| Uilleog | Irish | Diminutive form of Uilliam, the Iri.. | | |
| Uilliam | Irish | Common Irish form of William (resol.. | | |
| Uinseann | Irish | Gaelic form of Vincent (conquering).. | | |
| Uistean | Irish | Irish diminutive form of Hugh (hear.. | | |
| Ula | Irish | A Celtic name meaning "altar." | | |
| Ulick | Irish | Anglicized form of Uilleac and Uill.. | | |
| Una | Irish | Old name of debated meaning. Some b.. | | |
| Unity | Irish | Derived from the English unity (one.. | | |
| Valerie | Irish | A borrowing from the French, Valeri.. | | |
| Vanessa | Irish | An invention of Irish satirist Jona.. |  | |
| Vaughn | Irish | Transferred use of the surname deri.. | | |
| Vevina | Irish | Anglicized form of the Gaelic Bebhi.. | | |
| Vincent | Irish | A borrowing from the Old French, Vi.. | | |
| Vivian | Irish | A borrowing from the English, Vivia.. | | |
| Vivienne | Irish | A borrowing from the French, Vivien.. | | |
| Walter | Irish | Introduced by the Anglo-Normans, Wa.. | | |
| William | Irish | Introduced by the Anglo-Normans, Wi.. | | |
| Winifred | Irish | Derived from the Welsh Gwenfrewi, a.. | | |
| Yvonne | Irish | A borrowing from the French and Eng.. | | |
| Zaira | Irish | Invention of Irish writer C. R. Mat.. | | |
