Foclóir Mháirtín Uí Chadhain

Published here is the first half of the Royal Irish Academy’s edition of the extant, unpublished lexicographical work written and compiled between 1937 and 1946 by the writer, scholar and activist Máirtín Ó Cadhain (1906-70).

Máirtín Ó Cadhain undertook the compilation of this dictionary of Irish as used in his native Galway at the request of the Department of Education, and by 1937 had sent the first samples of his work which were intended, with similar material commissioned from other dialects, to form a basis for a large-scale Irish-English Dictionary; Foclóir Gaeilge-Béarla, edited by Niall Ó Dónaill, was published in 1977.

Ó Cadhain continued to send material in the following years, eventually ceasing in 1946, by which time he was well on the way to becoming one of the finest exponents of creative writing in Ireland in the 20th century. His groundbreaking novel, Cré na Cille, composed almost entirely in the common speech of his native Connemara, appeared in 1949, giving an enduring platform for his creative talent. Cré na Cille is now available in over a dozen languages.

Although more widely known as an exponent of the novel, the short story and the essay, here we meet Máirtín the lexicographer and the linguist, as he engages in deep and probing analysis and extrapolation of meaning and form in his native dialect. The dictionary, presented here for the first time, draws heavily on speech and idiom to elucidate the meaning and use of words, and thus it affords a unique and invaluable insight into Ó Cadhain’s perception and manipulation of his medium. His dictionary provides also a multidimensional view of the life and language of the Galway Gaeltacht from the first half of the 20th century, and is a linguistic and social document of immense importance to our understanding of Gaeltacht life and society in the period before the onset of irrevocable change.


Máirtín Ó Cadhain worked over a series of years and in varying contexts in compiling his dictionary material, including periods as an internee in Arbour Hill and the Curragh. The result is a large collection of manuscripts which he sent to An Gúm, filled with headwords and definitions, and accounts of their usage with fulsome provision of examples, containing in total over 1.1 million words of text.

The work presented on this website contains Ó Cadhain’s treatment of 748 headwords under the initial ‘D’, which comprises the letter of the dictionary which he completed most exhaustively. In his description of those 748 words, he gives over 1000 senses and more than 16,000 examples which range in length from short sentences to long, descriptive narratives, and contain also verses of poetry and song.

Ó Cadhain’s approach remained the same throughout his lexicographical work, in that under his headword he sought to provide all meanings for that word from the extent of his own knowledge, and to provide information and examples to demonstrate how that meaning could vary and differ, both in idiomatic context and throughout the sub-dialects of the region – he frequently differentiates between meaning in a particular area of Galway as opposed to another. In providing his examples he draws on placenames, on folklore and on song as well as on the speech of his neighbours and community, an approach which lends a unique human texture and social resonance to his work.


Three separate editions of the dictionary have been presented here:

  • Transcription: an edition remaining faithful to Ó Cadhain’s original spelling, available here;

  • Original Spelling: an edition which differs from the original only in the ordering and structuring of the material;

  • Modernised Spelling: an edition which presents the material in modern Irish spelling. This is the default edition, but users can click to view the edition in its original spelling at headword level.

The first step was to produce a digital transcription of Ó Cadhain’s manuscripts, gathered for the most part from the archive of An Gúm (the National Archives, University College Dublin, Trinity College Dublin and the National Library also contain elements of Ó Cadhain’s dictionary). More information is available here on the manuscripts of Ó Cadhain, and the method of transcription followed in the production of this edition.

When a transcription was completed, a list of headwords was extracted, and work began to assign the various usage examples to their proper place within a customised dictionary structure of senses and sub-senses. A full account of this is available in the editorial method, which outlines how a structure was customised in order to bring a uniform order to the material Ó Cadhain so painstakingly assembled.

As one might expect from a text compiled between 1937 and 1946, the spelling system within Ó Cadhain’s dictionary displays considerable variation and fluctuation. To ease the burden of understanding for the less-experienced reader, it was decided to produce a version of the dictionary which would be largely in keeping with the spelling conventions set by Foclóir Gaeilge-Béarla (1977) – a version in modernised spelling. An account of the editorial changes carried out is available here.

Links which have been provided throughout the dictionary allow headwords to be traced where they appear in a usage example under a different headword, giving users fuller access to Ó Cadhain’s account of word-use.

The editorial work on Foclóir Mháirtín Uí Chadhain was undertaken as part of the Academy’s ongoing work to produce Foclóir Stairiúil na Gaeilge, a comprehensive historical Dictionary of modern Irish.

This material is being published with the kind permission of An Gúm (Foras na Gaeilge); we are indebted also to Iontaobhas Uí Chadhain and to the Department of Tourism, Culture, Arts, Gaeltacht, Sport and Media for the support given to the project.