Ap Geiriaduron is as an English-Welsh/Welsh-English dictionary that can search for thousands of Welsh and English words offline.
The app uses a number of sources, including CysGair and ‘Y Termiadur Addysg’, that have over 25,000 Welsh and 25,000 English words between them.
You can also use the app to find rhyming words by using certain keywords.
A useful feature for those learning the language is that you can also un-mutate words, show verbs in infinitive forms and offers in depth information on any word.
Why not test your vocabulary with a friend using the app to check?
For more Welsh apps have a look at our apps page.