From Irish Pedigrees; or the Origin and Stem of the Irish Nation by John O'Hart
The following are some of the leading prefixes and affixes employed in the formation of Irish proper names:—
Beag or Beg, small.
Cineal or cinel, signifies "kindred, race, and descendants;" as Cineal Eoghain, "the descendants of Owen;" Cineal Connaill,"the descendants of Connell," etc.
Clann (or Clon) means "children, descendants, race;" as Clan-na-Mile [meel], "the descendants of Milesius;" Clan-na-Gael, "the descendants of Gaodhal," etc.
Fear [fhear], a man, fhear, the man, fir, feara, men, as feargaol, a relative; fir tire, "the men of the country": from which word "Vartry," a river in the county Wicklow, is derived.
Lis, a fort; as, Listowell, "the fort of Tuathal:" Lisburn, Lisdoonvarna, etc.
Mac, the son or descendant of; as Cormac MacAirt, "Cormac the son of Art; MacDonnell, "the descendants of Donall," etc.
Muintir, the people of. By this word, "Muintir," people, and "Cin," kindred, all families in Ireland were known before the introduction of
sirnames; as Cin Airt or Muintir Airt, "the people or kindred of Art," the 112th Monarch of Ireland; Muintir Eoghain, "the people of Owen," etc.
Ne, progeny; as Carrow-ne-kin-Airt, the Irish name for "Kinnaird"— a townland in the parish of Crossmolina, barony of Tyrawley, and county of Mayo: which means the (carrow or) quarter of land where settled some of the (ne or) progeny of the (kin or) offspring of the Monarch Art, who was called Art-Ean-Fhear, or, as it is contracted, "Art-Enear," the 112th Monarch, as above. And the name "Tiernaar," (or Tir-Enear), a barony in the west of Mayo, is, no doubt, similarly derived.
O', Ui, Hy, descendants of; as O'Brien, Ua-Hairt (or "O'h-Airt"), now O'Hart; Ui-Laeghaire, now O'Leary; Hy-Niall, "the descendants of Niall," etc. It may be observed that Hy is the plural of Ua or O, and is more correctly written Ui. The plural form denotes, therefore, the Clan, or the whole body of the descendants.
Og [oge], young; as Conchobhar (or Connor) og, meaning young Connor.
Rath, a fort stronghold; as Rathmore, etc.
Ruadh [rooa], red; this word is the root of the sirnames Roe and Rowe.
Tir or Tyre, a district, or territory; as Tyrawley, a barony in the county Mayo, which means "Awly's district;" Tirowen [tyrone], "Owen's district;" Tyrconnell, "Connall's district"—now the county Donegal.
Tullagh, a hill or green; as Tullaghoge, "the hill of the youths," now called "Tullyhawk," and situate in the parish of Desertcreaght, and barony of Dungannon. Tullaghoge was a green eminence in Tirowen, in the immediate territory of the O'Hagan's, who were the lawgivers of O'Neill, and were known as "Cineal-Owen of Tullaghoge:" where since the destruction of the palace of Aileach, A.D. 1101, the stone chair upon which The O'Neill was proclaimed, was preserved up to the year 1602, when it was demolished by Lord Mountjoy, then lord deputy of Ireland. "In the year 1602," writes Fynes Moryson, "the Lord Deputy Mountjoy remained here (at Tulloghoge) for five days, and brake down the chair wherein the O'Neills were wont to be created, being of stone planted in the open field."—See Fynes Moryson's Rebellion of Hugh Earl of Tyrone, Book iii., c. I.