Irish personal naming system

A formal Irish-language personal name consists of a given name and a surname. Surnames in Irish are generally patronymic in etymology, although they are no longer literal patronyms, as Icelandic names are. The form of a surname varies according to whether its bearer is male or female, and in the case of a married woman, whether she chooses to adopt her husband's surname.

An alternative traditional naming convention consists of the first name followed by a double patronym, usually with the father and grandfather's names. This convention is not used for official purposes but is generalized in Gaeltachtaí or Irish-speaking areas, and also survives in some rural non-Gaeltacht areas. Sometimes the name of the mother or grandmother may be used instead of that of the father or grandfather.

Epithets

A first name may be modified by an adjective to distinguish its bearer from other people with the same name. Mór ("big") and Óg ("young") are used to distinguish father and son, like English junior and senior, but are placed between the given name and the surname: Seán Óg Ó Súilleabháin corresponds to "John O'Sullivan Jr." (although anglicised versions of the name often drop the "O'" from the name).

The word Beag/Beg, meaning "little", can be used in place of Óg. This did not necessarily indicate that the younger person was small in stature, merely younger than his father. Sometimes beag would be used to imply a baby was small at birth, possibly premature.

Adjectives denoting hair colour may also be used, especially informally: Pádraig Rua ("red-haired Patrick"), Máire Bhán ("fair-haired Mary").

Surnames and prefixes

A male's surname generally takes the form Ó/Ua (meaning "descendant") or Mac ("son") followed by the genitive case of a name, as in Ó Dónaill ("descendant of Dónall") or Mac Gearailt ("son of Gerald").

A son has the same surname as his father. A female's surname replaces Ó with Ní (reduced from Iníon Uí - "daughter of descendant of") and Mac with Nic (reduced from Iníon Mhic - "daughter of the son of"); in both cases the following name undergoes lenition. However, if the second part of the surname begins with the letter C or G, it is not lenited after Nic. Thus the daughter of a man named Ó Dónaill has the surname Ní Dhónaill and the daughter of a man named Mac Gearailt has the surname Nic Gearailt. When anglicised, the name can remain O' or Mac, regardless of gender.

If a woman marries, she may choose to take her husband's surname. In this case, Ó is replaced by Bean Uí ("wife of descendant of") and Mac by Bean Mhic ("wife of the son of"). In both cases bean may be omitted, in which case the woman uses simply Uí or Mhic. Again, the second part of the surname is lenited (unless it begins with C or "G", in which case it is only lenited after Uí). Thus a woman marrying a man named Ó Dónaill may choose to be use Bean Uí Dhónaill (Mrs. O'Donaill in English) or Uí Dhónaill as her surname; a woman marrying a man named Mac Gearailt may choose to use Bean Mhic Gearailt (Mrs Mac Gearailt) or Mhic Gearailt.

If the second part of the surname begins with a vowel, the form Ó attaches an h to it, as in Ó hUiginn (O'Higgins) or Ó hAodha (Hughes). The other forms effect no change: Ní Uiginn, (Bean) Uí Uiginn; Mac Aodha, Nic Aodha, Mhic Aodha, and so forth.

Mag is often used instead of Mac before a vowel or (sometimes) the silent fh. The single female form of "Mag" is "Nig". Ua is an alternative form of Ó.

Some names of Norman origin have the prefix Fitz, from Latin filius "son", such as Fitzwilliam, Fitzgerald, and so forth. Other Norman surnames may have the prefix "de", such as de Búrca, de Paor, or de Róiste.

Male	Meaning	Anglicised	Daughter	Wife	Examples
Mac	son (of)	Mc/Mac/M'	Nic	Mhic	Seán Mac Mathúna, Máire Mhic Mhathúna (wife of Seán), Aoife Nic Mhathúna (daughter of Seán)
Ó/Ua	descendant of	O'	Ní	Uí	Pól Ó Murchú, Mairéad Uí Mhurchú (wife of Pól), Gráinne Ní Mhurchú (daughter of Pól)

Patronyms and other additives

Many Irish surnames are concentrated in particular parts of the country and there are areas where a single surname may account for a large proportion of the population. Examples include O'Reilly in County Cavan, Ryan in County Tipperary and East County Limerick, or O'Sullivan in the Beara peninsula of West Cork; or areas, such as Glenullin in the Sperrins, where there are several dominant surnames (in that instance O'Kane, Mullan, McNicholl and some others). In such cases, the surname may also acquire an additive in popular usage to differentiate one group bearing the same surname from another.

This sometimes originates as a simple patronym – that is, a James whose father was Harry might be referred to as Harry's James – but may be passed to later generations, so that James' son Pat might be Harry's Pat. This can also occur if a person becomes well known by a nickname: his children may take his nickname as an additive. For example, if Seán O'Brien was often referred to as "Badger", his son Patrick might be referred to orally as Pat Badger and written as Patrick O'Brien (B).

In Tipperary, additives are particularly common among those bearing the Ryan surname. Examples include Ryan Lacken, Ryan Luke and Ryan Doc. A man christened Thomas Ryan might be known as Tommy Doc and his family might be referred as the Docs. While the additive is not part of a person's official name, it may be used in a postal address, on an election register or in newspaper reports. In this case, Tommy Doc might be written as Thomas Ryan (D).

Traditional Gaeltacht names

In Gaeltacht (Irish-speaking) areas it remains customary to use a name composed of the first name, followed by the father's name in the genitive case, followed by the name of the paternal grandfather, also in the genitive. Thus Seán Ó Cathasaigh (Sean O'Casey), son of Pól, son of Séamus, would be known to his neighbours as Seán Phóil Shéamuis. Occasionally, if the mother or grandmother was a well-known person locally, her name may be used instead of that of the father or grandfather. If the mother's name is used, then that of the maternal grandfather (or potentially grandmother) follows it, for example, Máire Sally Eoghain.

These names are not used for official purposes. Often a nickname or English version of a name is used in their composition where the person would use a standard Irish form in formal circumstances. For example, the prominent sean-nós singer Seán Mac Dhonnchadha is perhaps better known as Johnny Mhairtín Learaí.

This naming system also survives to a certain extent in rural areas outside the existing Gaeltacht. The system can be particularly useful for distinguishing individuals who live in the same locale, and who share a common surname but are not closely related. For example, two individuals named John McEldowney might be known as "John Patsy Den" and "John Mary Philip" respectively. Even the Irish forms sometimes survive in parts of the Sperrins, so that among the principal families of Glenullin some branches are known by father/grandfather forms such as Pháidí Shéamais or Bhrian Dhónaill.

Examples of firstnames and surnames

Notable examples of firstnames and surnames

Many Irish people use English (or at least anglicised) forms of their names in English-language contexts and Irish forms in Irish-language contexts. The Irish names of some famous people include:

English/Anglicised name	Irish name	Notes
Bertie Ahern	Parthalán Ó hEachthiarn	Taoiseach from 1997 to 2008.
Thomas Ashe	Tomás Ághas	Gaelic League member
Harry Boland	Éinrí Eoin Ó Beólláin
Moya Brennan	Máire Ní Bhraonáin	Irish-language spelling as birth name
Turlough Carolan	Toirdhealbhach Ó Cearbhalláin	Irish harpist and composer
Edward Carson	Éamon Mac Arsúin	Unionist leader
Erskine Childers	Earchta Ó Slatiascaigh	(Irish author and patriot, also his son - President of Ireland -, and grandson)
Michael Collins	Mícheál Eoin Ó Coileáin	signed Anglo-Irish Treaty with Irish-language name
Michael Corcoran	Mícheál Ó Corcráin	Union Army General
Liam Cosgrave	Liam Mac Cosgair	William(?) Thomas Cosgrave (the son), Taoiseach
W. T. Cosgrave	Liam Tomás Mac Cosgair	William Thomas Cosgrave (the father), President of the Executive Council
Michael Joe Costello	Mícheál Seosamh Mac Oisdealb	Irish Army General
Garret FitzGerald	Gearóid Mac Gearailt	twice Taoiseach
Arthur Griffith	Art Ó Gríobhtha	Gaelic League member; Sinn Féin founder and leader; bilingual signature on Anglo-Irish Treaty
Patsy O'Hara	Peatsaí Ó hEadhra
Charles Haughey	Cathal Ó hEochaidh	three times Taoiseach
Michael D. Higgins	Micheál Ó hUiggin	9th President of Ireland
Douglas Hyde	Dubhghlas de hÍde	1st President of Ireland; CnaG founder
Sir William Johnson, 1st Baronet	Liam Mac Seáin	1st of the Johnson Baronets of New York
John Fitzgerald Kennedy	Seán Mac Gearailt Ó Cinnéide	35th President of the United States
Kitty Kiernan	Caitríona Nic Thiarnáin	fiance of Michael Collins (Irish leader)
Jack Lynch	Seán Ó Loingsigh	twice Taoiseach
Mary McAleese	Máire Mhic Ghiolla Íosa	née Mary Leneghan/Máire Ní Lionnacháin
Kevin McCarthy	Caoimhín Mac Cárthaigh	Actor
Liam Mellows	Liam Ó Maoilíosa
Thomas Mooney	Tomás/Tomaltach Seosamh Ó'Maonaigh	Labor Leader
Dr. Trevor Morrow	Trebhar Mac Murchadha	Former Presbyterian Church in Ireland Moderator
Richard Mulcahy	Risteárd Ó Maolchatha	Old IRA/Irish Army Chief of Staff
Dennis O'Brien (policeman)	Denis Ó Briain
JJ "Ginger" O'Connell	Irimia Seosamh O'Conaill	Irish Army officer
Kevin O'Higgins	Caoimhín Ó hUiginn	Minister of Justice and Vice-President; not to be confused with the more recent official also in the Department of Justice, Equality and Law Reform
Seán T. O'Kelly	Seán T. Ó Ceallaigh	Vice-President, first Tánaiste, President of Ireland
Francis O'Neill	Proinsias Ó Néill
Thomas Francis O'Rahilly	Tomás Phroinsias Ó Rathaille	scholar of Celtic language and culture; sometimes also "Rahilly" or "Rahily"
Joseph O'Sullivan	Seosamh Ó Súilleabháin	(likely very common name)
Patrick Pearse	Pádraig Mac Piarais	CnaG; An Claidheamh Soluis editor; St. Enda's School founder
Joseph Mary Plunkett	Seosamh Máire Pluincéad	Gaelic League member; an Easter Uprising leader
John Edward Redmond	Seán Éamonn Mac Réamainn
Albert Reynolds	Ailbhe Mac Raghnaill	Taoiseach
Mary Robinson	Máire Bean Mhic Róibín	(née Máire de Búrca)
Cornelius Ryan	Cornelius Ó Riagháin	War correspondent and author
Paddy Ryan	Padric Ó Riagháin	Irish American Heavyweight boxer
Robert Gerard Sands	Roibeárd Gearóid Ó Seachnasaigh
Austin Stack	Aibhistín de Staic
John L. Sullivan	Sean Ó Súilleabháin	Irish-American Boxing heavyweight Champion of the World
Gerard Toal	Gearóid Ó Tuathail

Other people are better known by their Irish name than by their English name:

Irish (Gaelic) name	English/Anglicised form	Notes
Dubhaltach Mac Fhirbhisigh	Dudley Forbes	though neither Dubhaltach or Fibrisigh correspond to the Anglicised forms
Ruaidhrí Ó Flaithbheartaigh	Roderick O'Flaherty
Flaithrí Ó Maolconaire	Florence Conry	(1560–1629, Archbishop of Tuam)
Gráinne Ní Mháille	Grace O'Malley	many other Irish-language and English-language respellings of her name also exist
Seán Bán Breathnach	"White" John Walsh
Séamus Ó Grianna	James Greene	though Grianna does not correspond etymologically to the English name "Green" or "Greene"
Gráinne Seoige	Grace Joyce
Eiléan Ní Chuilleanáin	Ellen Cullen
Antoine Ó Raifteiri	Anthony Raftery
Proinsias De Rossa	Frank Ross
Pádraig Harrington	Patrick Harrington
Pádraig Ó Riain	Patrick Ryan
Pádraig Ó Siochfhradha	Patrick O'Sugrue
Padraig Ó Síocháin	P. A. Sheehan
Pádraig Ó Fiannachta	Patrick Finnerty
Lorcan Ua Tuathail	Laurence O'Toole
Dara Ó Briain	Darragh O'Brien
Doireann Ní Bhriain	Doreen O'Brien
Cathal Brugha	Charles William St. John Burgess
Éamon de Valera	Edward De Valero

See also

• Celtic onomastics
• Irish toponymy
• Scottish Gaelic personal naming system
• Welsh surnames

External links

• Irish Names at LibraryIreland.com
• The Origins of Irish Surnames at IrishTimes.com
• Find Irish Family Names at Dubliner.com
• Irish surnames and Y-DNA at AncestralJourneys.org