National Library of Ireland, Manuscript G11 403a10. Image, Irish Scripts on Screen

Researchers from Cambridge and Queen’s University Belfast have identified and defined 500 Irish words, many of which had been lost, and unlocked the secrets of many other misunderstood terms. Their findings can now be freely accessed in the revised version of the online dictionary of Medieval Irish (

The Dictionary offers a window onto a fascinating and important past world

Máire Ní Mhaonaigh

If you were choosing where to live in medieval Ireland you might insist on somewhere ogach which meant ‘eggy’ or ‘abounding in eggs’, but in reference to a particularly fertile region. By contrast, you would never want to hear your cook complaining brachaid, ‘it oozes pus’. And if you were too boisterous at the dining table, you might be accused of briscugad (making something easily broken).

All three words have been brought back to life thanks to a painstaking five-year research project involving a collaboration between Queen’s University Belfast and the University of Cambridge. The team has scoured medieval manuscripts and published texts for words which have either been overlooked by earlier dictionary-makers or which have been erroneously defined.

Máire Ní Mhaonaigh, Professor of Celtic and Medieval Studies at Cambridge says: “The Dictionary offers a window onto a fascinating and important past world. The project extends our understanding of the vocabulary of the time but also offers unique insights into the people who used these words. They reveal extraordinary details about everyday lives, activities, beliefs and relationships, as well as contact with speakers of other languages.”

The revised dictionary spans the development of the Irish language over a thousand years from the sixth century to the sixteenth, from the time just after the arrival of St Patrick all the way down to the era of Elizabeth I. The team has amended definitions, presented evidence to show that some words were in use much earlier than previously thought, and even deleted a few fake words. One of these is tapairis which had been taken to be some kind of medicinal substance but in effect is not a word at all, since it arose from an incorrect division of two other words literally meaning ‘grains of paradise’, the term for Guinea grains.

Lost words

The rediscovered lost words include a term for ‘becomes ignorant' – ainfisigid, based on the word for knowledge: fis. Other words have been shown to have been attested hundreds of years earlier than was previously thought, such as foclóracht meaning vocabulary. Yet, other examples emphasise that the medieval world continues to resonate. One of these is rímaire, which is used as the modern Irish word for computer (in its later form ríomhaire). 

Professor Ní Mhaonaigh explains: “In the medieval period, rímaire referred not to a machine but to a person engaged in the medieval science of computistics who performed various kinds of calculations concerning time and date, most importantly the date of Easter. So it’s a word with a long pedigree whose meaning was adapted and applied to a modern invention.”

The historical dictionary on which the electronic one is based was originally published by the Royal Irish Academy in 23 volumes between 1913 and 1976. “Advances in scholarship since the publication of the first volume had rendered parts of the dictionary obsolete or out of date,” says Greg Toner, leader of the project and Professor of Irish at Queen’s University Belfast. “Our work has enabled us to resolve many puzzles and errors and to uncover hundreds of previously unknown words.”

The online Dictionary serves up a feast of information on subjects as diverse as food, festivals, medicine, superstition, law and wildlife. One of the newly added phrases is galar na rig, literally the king's disease, a term for scrofula which is known in English as king's evil.

Outlaws and turkeys

The project sheds new light on Ireland’s interactions with foreign languages, cultures and goods in the medieval period. The Dictionary points out that útluighe, meaning an outlaw, ultimately goes back to the Old Norse word útlagi, though the term was perhaps borrowed into Irish through English or Anglo-Norman. Its use appears to have been limited – the researchers have only found it once, in a thirteenth-century poem by Giolla Brighde Mac Con Midhe.

Another loanword in Modern Irish is turcaí (turkey) but before this was borrowed from English, this bird was known as cearc fhrancach (turkey hen) or coilech francach (turkey cock). Strictly speaking, the adjective Francach means 'French' or 'of French origin'. This usage to denote a bird native to the Americas may seem odd but in other languages, it is associated with various countries including France, for reasons which remain unclear.

Spreading the word

Professor Toner says: “A key aim of our work has been to open the Dictionary up, not only to students of the language but to researchers working in other areas such as history and archaeology, as well as to those with a general interest in medieval life.”

In a related project, the researchers have been developing educational resources for schools in the United Kingdom and the Republic of Ireland.

The Dictionary launched on 30 August 2019 at the Royal Irish Academy, Dublin. A History of Ireland in 100 Words, drawing on 100 of the Dictionary's words and tracing how they illuminate historical changes will be published in October 2019 by the Royal Irish Academy

For more on the newly discovered words, see a piece by Dr Sharon Arbuthnot, a researcher on the project, in the Brainstorm series on National Irish Television (RTÉ).


Work on the Dictionary has been supported by the UK’s Arts and Humanities Research Council. The related project developing schools’ resources is funded by a grant from the University of Cambridge, School of Arts and Humanities Impact Fund.

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