It is quite obvious from the whole testimony of authentic Irish history that the names of tribes in Ireland were not derived from the territories and localities in which they dwelt, but from distinguished ancestors; for nine-tenths of the names of territories, and of the names of the tribes inhabiting them, are identical. The tribe names were formed from those of the progenitors, by prefixing the following words:—
1. Corc, Corca, race, progeny, as Corc-Modhruadh, now Corcomroe in Clare, Corca-Duibhne, now Corcaguinny in Kerry.
2. Cineal, race, descendants; cineal Eoghain, the race of Eoghan; cineal Conaill, the race of Conall. This word is translated Genus throughout the Annals of Ulster.
3. Clann, children, descendants; as clann Colmain, the tribe name of a great branch of the southern Hy-Niall.
4. Dal, tribe, descendants, as Dal-Riada, Dal-Araidhe, Dal-g-cais, Dal Mesincorb, &c. This word has been explained by the venerable Bede, and from him by Cormac Mac Cullenan, archbishop of Cashel, as signifying part or portion in the Scottic language; but from the manner in which it is used in Irish genealogies, this would appear to be but a secondary and figurative meaning. O’Flaherty seems to doubt that this word could be properly translated part; but Charles O’Conor, who gave much consideration to the subject, writes in a note to Ogygia Vindicated, p. 175, “that dal properly signifies posterity, or descent by blood; but in an enlarged and figurative sense it signifies a district, that is, the division or part allotted to such posterity: that of this double sense we have numberless instances, and that in this second sense Bede’s interpretation is doubtlessly admissible.”
5. Muintir, family, people; as Muintir Murchadha, the tribe name which the O’Flahertys bore before the establishment of surnames.
6. Siol, seed, progeny; as Siol Aodha, seed of Hugh, the tribe name of a branch of the Mac Namaras in Thomond; Siol Maoluidhir, the progeny of Maeleer, a great tribe in Leinster, who gave name to the territory of Shelmalier, in the county of Wexford.
7. Tealach, family; as Telach Eathach, the family of Eochy, the tribe name of the Magaurans in Breffney.
8. Sliocht, posterity; as Sliocht Aodha Slaine, the progeny of King Hugh Slany in Meath.
9. Ua, grandson, descendant; nominative plural, ui; dative or ablative, uibh. This prefix in its upright uninflected form appears in the names of Irish tribes oftener than any of the other seven. Some ignorant Irish scribes have supposed that it signifies a region or country, and some of the modern transcribers of Keating’s History of Ireland have taken the liberty to corrupt it to aoibh, a form not to be found in any ancient or correct MS. In support of the meaning above given may be adduced the high authority of Adamnan, abbot of Iona in the 7th century, who, in his life of his predecessor St Columbkille, invariably renders ua, ui, uibh, nepos, nepotes, nepotibus, in conformity with his habitual substitution of Latin equivalents for Irish tribe names, as often as he found it practicable. Thus, in the 16th chapter of the second book, he renders Ua Briuin, nepos Briuni; in the 5th chapter of the third book he translates Ua Ainmirech, nepos Ainmirech; in the 17th chapter of the same book he translates Ua Liathain, nepos Liathain; in the 49th chapter of the first book he renders Ui Neill, nepotes Nelli, i.e., the race of Niall; and in the 22d chapter of the same book he translates Ui Tuirtre, nepotes Tuitre.