App Support


This section contains information and answers to FAQ’s for users of our Android and iOS apps.
These guidelines are also available within the app.
If you require any additional help please submit your enquiry to
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About the Dictionary

About the app

What is GPC?

Geiriadur Prifysgol Cymru is a standard historical dictionary of Welsh similar in plan and status to the Oxford English Dictionary. It presents the vocabulary of Welsh from the earliest texts of the eighth and ninth centuries right up to the present day. It was prepared by a team of researchers over a period of 90 years. It is regularly extended and the older entries are revised. The date of publication of the entries varies between 1950 and this year, and is given after the headword.
Definitions are in Welsh, with English synonyms. Detailed attention is paid to variant forms, collocations, and etymology. With this app it is possible to search the headwords, variants, collocations, and cross-references. Also, by choosing to search for English words, the English synonyms can be searched.
It is possible to search for part of a word (e.g. searching for ‘+gi’ will find every entry which ends with ‘…gi’, such as bolgi and celwyddgi). It is also possible to search for more than one word (e.g. searching for ‘byth a’ will find byth a beunydd, byth a hefyd, and beunydd a byth).

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How big is GPC?

GPC is a large dictionary, containing:

  • 87,472 entries
  • 124,461 headwords
  • 89,102 etymological sections
  • 106,074 main senses
  • 7,152 variants
  • 34,416 collocations
  • 473,481 illustrative quotations
  • 4,697 different bibliographical sources
  • over 8 million words in total.

The app’s full database takes about 185MB of storage, but a shorter version, which excludes the illustrative quotations, is available, which is about 132MB. The app itself is small (about 1MB) and can be used without downloading the data, see The app takes too much space. What can I do?

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When was GPC written?

The original publication date for each entry is shown to the right of the headword, between brackets.
The first edition of GPC appeared between 1950 and 2002 and the second edition is in progress. Most of the A–B section has been thoroughly revised, and the second edition entries can be seen here. From C onwards the editors are adding new entries and re-editing a selection of existing entries. The latest work will be added regularly to GPC Online and the app.

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Which is the standard spelling/gender/form?

GPC aims to follow standard Welsh orthography in the spelling of headwords and plural forms, variants, and collocations. The form which appears first is the most common today. This also applies to gender and the plural forms listed. With verbs, the most standard verb-noun is placed immediately after the colon.
With names, the gender noted first is the most common in the literary language, but remember that the gender of words can vary in different areas.
The spelling of the illustrative quotations follows the original text. Texts are sometimes quoted from editions which have standardized the orthography: these are quoted exactly as they appear in the edition.

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How do I use the app and change the language?

The interface is available in Welsh or English. You can change the interface language when the app starts or by selecting either ‘English’ or ‘Welsh’ in the Settings (tap ◄GPC (several times), then Settings / Interface language). (This does not change the language of the words you will be searching for in the Dictionary, just the interface itself.)
At the top of the screen are several controls:

  • Tapping ◄GPC takes you to the previous section and to the main menu (you may need to tap it several times).
  • ‘WEL’ at the top of the screen indicates that Welsh words will be searched. Tap this to change it to ‘ENG’ in order to search for English words.
  • Tapping the magnifying glass will open a search box you can type in.
  • The arrows take you back and forth through recent screens.

After searching, a list of results will appear. Any one of these can be tapped to see the appropriate entry. (In landscape mode the first result will be displayed automatically on the right.)
Tap any abbreviation to see the full word or an explanation.
The numbers at the top left of the entry indicate the position of this result in the list of results (e.g. 2/64 indicates that this is the 2nd of 64 results). To see the next result you can ‘swipe’ from right to left and to go back you can ‘swipe’ from left to right (think of flicking through a book).
The illustrative quotations can be revealed by tapping the Button plus sign button on the right, and hidden by tapping the Button minus sign button. Tapping the Button plus sign button at the top of the screen reveals all the quotations throughout the entry.
Tap the abbreviation of any title in a quotation to see the full details.
The grey panel at the bottom of each entry permits you to examine nearby entries and it can be scrolled left or right to see further words. You can tap any of these to display the corresponding entry.
If the text is too small or too large, you can spread your fingers on the screen to expand it or pinch the screen to contract it – in the usual way.
You can also copy text from the app into another app in the usual way.

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How do I search for a Welsh word or phrase?

You can search for a word or phrase by typing it in the search box at the top of the screen. Accents, apostrophes, the case of letters, and numbers are all ignored to make searching easier. The app also searches automatically for any mutated forms.
When ‘WEL’ appears, at the top of the screen, you can search for a Welsh word or phrase. If ‘ENG’ appears, tap on it to change it to ‘WEL’.
You can use:
* instead of 0, 1, or more letters (e.g. cam*waith finds campuswaith, campwaith, and camwaith; *z* finds all words containing the letter z)
+ instead of 1 or more letters (e.g. cam+waith finds campuswaith and campwaith)
? instead of 1 letter (e.g. c?o?s??r finds croesair, clocsiwr, croesbar, etc.)
Word order does not have any effect when searching for phrases or collocations, so baw jac will find jac y baw, jac codi baw and jac llwyd y baw.

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How do I search for an English word or phrase?

GPC is a historical dictionary of the Welsh language, dealing with Welsh words from every period, having its definitions in Welsh, together with English synonyms. It is not an English–Welsh dictionary. However, searching for an English word may remind you of the corresponding Welsh word. You may, for example, look for river, which finds the entries for aber, afon, and nant and over a hundred other definitions containing the word.
When ‘ENG’ appears above, you can search for an English word or phrase. If ‘WEL’ appears, tap on it to change it to ‘ENG’.
Word order does not have any effect when searching, so bible dictionary will also find dictionary of the Bible.
You can use:
* instead of 0, 1, or more letters (e.g. zoolog* finds zoology, zoologist, and zoological; nat* lib* finds national library)
+ instead of 1 or more letters (e.g. river+ finds river-bank, river-bed, and riverside, ignoring over 100 examples of river on its own)
? instead of 1 letter (e.g. c?o?s??r finds crossbar and cloister)
The results can refer to articles or collocations.

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Is there any difference between GPC Online and this app?

The app uses exactly the same data as GPC Online and both can be searched in exactly the same way. The app has the advantage that it has been designed to be used on smaller screens and you do not need Internet access: you can download the data onto your device, see How can I download the data?
The main difference is that you cannot see images of the original printed pages in the app: you must use GPC Online.
There are word games in the app which are not available in GPC Online, see How do I play the word games?

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Do I have to be online to use the app?

No, provided you have enough storage space in your device to store the data locally. If you want to keep a local copy, tap ◄GPC (several times), then Settings / Database. Select the basic database (everything except the quotations, taking about 132MB) or the full database (everything, about 185MB).

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How can I download the data?

The dictionary data can be downloaded as a full database which contains everything or as a basic database which excludes the illustrative quotations to save space on your device. This can be done within Settings (tap ◄GPC (several times), then Settings / Database). Select the type of database required and follow the instructions. You can continue using the app while the database is being downloaded.
If you are using the basic database and want to see the quotations, you could temporarily change to the remote database within the Settings and use WiFi or mobile data, and then switch back again to using the basic database. This will not delete the database.
The content of the Dictionary is updated regularly. If you want to get the latest version of the data, delete the database within Settings (tap ◄GPC (several times), then Settings / Databases / Manage local databases). After deleting the database, if you then select a local database again, you can download the latest database.

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How do I play the word games?

There are two games based on the Dictionary’s content: Hidden words and Anagrams. Both games can be restricted to the Welsh words searched since opening the app and this can be a good way for learners to practise their new vocabulary: tap ◄GPC (several times), then Settings / Words for the games. Tapping Clue shows the Welsh definition or the English one depending on the interface language.
Anagrams: tiles must be moved by dragging them into the correct order.
Hidden words: note that there is only one hidden word. It can run in any direction. The correct tiles must be tapped to reveal the word.
You will get a message when you succeed. In both games New word restarts the game with a different word. If you need to see the entry for the word at any time, tap Answer. After seeing the entry, you can tap on the arrow pointing to the left to go back to the game.

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How can I cite from the app?

If you want to cite one of the GPC articles in an academic publication, it is recommended that you use the distant database (in order to ensure that you use the latest data: tap ◄GPC (several times), then Settings / Database / Remote database). You can adapt one of the following examples:
MLA Style: “pen1” Geiriadur Prifysgol Cymru Online. Centre for Advanced Welsh and Celtic Studies, 2016. The Internet. [date accessed in the format 1 December 2016].
Chicago Style: “pen1”. Geiriadur Prifysgol Cymru Online. 2016. Centre for Advanced Welsh and Celtic Studies, 2016. (accessed [date accessed in the format 1 December 2016]).
Harvard Style: Geiriadur Prifysgol Cymru Online. 2016. “pen1” [Online]. Aberystwyth: Centre for Advanced Welsh and Celtic Studies. Available in: [Accessed: [date accessed in the format 1 December 2016]]

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The app takes too much space. What can I do?

The app itself does not take much space on the device, but because of the size of the Dictionary, the full database is large (185MB). To save space, you can delete the database. If you are using the full database, you can delete it within the Settings (tap ◄GPC (several times), then Settings / Database / Managing local databases) and download the basic database which takes less space (132MB) as it excludes the illustrative quotations. If that does not release enough space, you can delete it – but then you must always have an Internet connection to use the app.

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How can I get more help?

If you have difficulty using the Dictionary or would like to ask a question about a specific word, you can contact us through:

For more information about the Dictionary, go to

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