What’s in a Name? Decoding the Rules of Irish-Language Names.

Irish names can appear daunting to non-native-speakers at first glance. There appear to be all those extra consonants, oodles of silent letters, and erratic capitalization. Then there’s the matter of the extra words between the surname and first names; what are they about?

Map of Irish names

The Family Names of County Cork. Detail from storymaps.esri.com

Male Surname Prefix

Let’s demystify the meaning of Irish names, starting with the male prefixes, as those are the ones more people are familiar with.

Mac — means “son of” — anglicized as Mc or left as Mac.

Ó — means “grandson of” — anglicized as O’.

I should say that Mac and Ó originally meant son of or grandson of, because today family names are usually settled and don’t change with the generations. 

Common names in the Gaeltacht

Hello My Name IsAn older tradition can still be seen in Gaeltacht areas, where men were traditionally known by three names: their name, their father’s first name, and their grandfather’s first name (but they still have their formal/official name as well). For example, I would be Risteárd Éadbhard Liam. This highlights the historical importance of names as a means of identifying ones clan membership. Like so many traditions, this one is also dying out, but isn’t quite gone yet.


The importance of names and establishing connections is visible in everyday conversation between Irish people. It’s become a cliche that parents drive their children crazy by constantly asking for clarification about who their friends’ parents are, but it’s true.

“What were ye at?”

“Playing football with Conor and Mackie.”

“I don’t know Conor. What’s his family name?”


“From over Nobber direction?”


“Is his father Patsy, the car mechanic?”

“No, his father’s a butcher.”

“Oh. I wonder if he’s a cousin so… Your uncle used to play football with Patsy O’Sullivan — on the Meath minors!”


We’re obsessed with establishing connections and roots. It probably goes back to the days of the Gaelic tribes and the Brehon laws, where people could be held legally responsible for the actions of another member of their clan. If a man killed somebody unjustly or stole property, his extended clan would have to compensate the injured party. Still later, when Ireland was occupied by the English, strangers were treated with suspicion until they could prove some level of connection to the families and clans of the area. (They might otherwise have been a spy.) The various legends and sagas contain a wealth of familial history and lines of descent. Maybe that’s why Irish parents work so hard to weave everybody into the web of parish connections?

Diminutives and Epithets

The practice of referring to somebody by their father and grandfather’s names is also useful because, in many small communities, the same names are often recycled through families as a means of honoring our forebears (a practice that seems to be common across cultures). So, listing the genealogy in the name clarifies a person’s identify and place in the community quickly. This also accounts for the widespread use of nicknames like Og (young), beag (little or young), Mór (big or old) or rua (red) to distinguish between people with the same name.

Female Surname Prefix

Women are distinguished through their patriarchs in a similar way, but the prefixes and modifications are different.

Ó (grandson of) becomes (granddaughter of)

Mac (son of) becomes Nic (daughter of)

For example, if the father’s name is Ó Laoghaire the daughter’s name is Ní Laoghaire, and if the father’s name is Mac Riada, the daughter’s name is Nic Riada. Confused? Well, it gets more complicated…


Name Changes After Marriage

Gaelic language wedding inviteWhen a woman marries, her name will change again. She’s no longer a daughter or granddaughter, she literally become a “wife of somebody’s son” (Bean Mhic) or a “wife of somebody’s grandson” (Bean Uí). In practice, few women choose to use the Bean (wife) as their formal name, and instead insert the Mhic or Uí before their husband’s family name. So, if Áine Ní Laoghaire married a man named Ó Néill she would become Áine Bean Uí Néill. This means that a mother, father and their child can all appear to have different last names, although in reality they aren’t.

There are several other rules that come into play if the husband’s family name starts with certain letters, but I won’t go into those.

Names, as you can see, mean a lot to the Irish. The British tried to anglicize and standardize the complicated system of Irish-language names, (hence O’Neill is now more common than Ó Néill, for one example), but people are actively asserting the Irish roots of their names and many now use the Irish versions of their names. There’s a lot of information contained in those seemingly confusing and unpronounceable names, but they’re not that difficult to decode when you know the meaning they’re intended to convey.



Other post you might enjoy:

Climbing Kildare’s Round Tower…

Imbolc: The Promise of Spring…

Take a self-guided road trip through the Irish locations seen in Game of Thrones





  1. Lois Farley Shuford’s avatar

    Good post – One of my grad students once worked for a summer in Ireland – his name was something completely unIrish (like Goldsmith) but his grandmother’s name was Kelly, and he was always introduced as “Jim Goldsmith, he’s a Kelly.”
    My cousin was asked on his first visit to Ireland if he was an English Farley or an Irish Farley. Definitely the Irish variety – the spelling evolved after a generation or two from Farrelly to Farley. I like the original better.

    1. Rich Rennicks’s avatar

      I think the original Irish of Farrelly would have been Ó Fearghaile. Tracing Irish family history is always a nightmare because of all the spelling changes.

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