The University of Wales' Dictionary of the Welsh Language — Geiriadur Prifysgol Cymru or GPC for short — is now available online in a full version that is freely accessible.
The only standard historical dictionary of Welsh, it has been described as comparable in method and scope with the Oxford English Dictionary.
Managing editor Andrew Hawke writes that the online dictionary
allows the user to search for Welsh headwords, variant forms, and collocations, as well as synonymous words and phrases in the English definitions. The vocabulary is defined in Welsh with English synonyms, so GPC is not intended to be used as a translating dictionary. However, when the English definitions are searched, the results are ordered according to the relevance of the searched term in the definition, so as to give precedence to synonymous words.
The dictionary is available in English at welsh-dictionary.ac.uk. For those conversant in the Language of Heaven, the Welsh-language site is geiriadur.ac.uk. Their Twitter account, @geiriadur, sends out a word of the day.