Welcome to Geiriadur Prifysgol Cymru
GPC is the only standard historical dictionary of the Welsh language.
It is broadly comparable in method and scope to the Oxford English Dictionary.
It presents the vocabulary of the Welsh language from the earliest Old Welsh texts, through the abundant literature of the Medieval and Modern periods, to the huge expansion in
vocabulary resulting from the wider use of Welsh in all aspects of life in the last half century.
This vocabulary is defined in Welsh, and English equivalents are also given. Detailed attention is given to variant forms, collocations, and etymology.
The work is based on an ever-expanding collection of over two million citation slips gathered from a range of texts over many years.
Staff are now using the latest technology to gather evidence in digital form and to edit the Dictionary, updating its contents regularly.
In 2014 a free online version of the Dictionary was published: GPC Online, containing all the material in the first and second editions, together with thousands of new or revised entries which have been added since then.
Mobile apps for Apple and Android phones were launched in 2016 with Welsh Government funding, which are free and give access to the whole wealth of the Dictionary. The app is now also available on Amazon Fire tablets.
The Dictionary is a research project within the University of Wales Centre for Advanced Welsh and Celtic Studies on the site of the National Library in Aberystwyth and is funded by the Welsh Government and the University of Wales Trinity Saint David.