Geiriadur Prifysgol Cymru

Geiriadur Prifysgol Cymru (GPC) (The University of Wales Dictionary) is the only standard historical dictionary of the Welsh language, aspiring to be "comparable in method and scope to the Oxford English Dictionary". Vocabulary is defined in Welsh, and English equivalents are given. Detailed attention is given to variant forms, collocations, and etymology.^[1]

The first edition was published in four volumes between 1967 and 2002, containing 7.3 million words of text in 3,949 pages, documenting 106,000 headwords. There are almost 350,000 dated citations dating from the year 631 up to 2000, with 323,000 Welsh definitions and 290,000 English equivalents, of which 85,000 have included etymologies.