"The third book."
Translation:Y trydydd llyfr.
With ordinals (number adjectives) they come before the noun except for cyntaf (first) which is actually an ordinary adjective as well (meaning 'earliest'):
- y llyfr cyntaf - the first book (the earliest book)
- yr ail lyfr - the second book
- y pumed llyfr - the fifth book
- yr ugeinfed llyfr - the twentieth book
Things get a liitle more complex with ordinals such as 'eleventh', 'thirteenth' and so on, where the ordinal splits around the noun, but I don't think that is covered on this course. For example, with dates it is quite straightforward as there is no noun involved:
- yr unfed ar ddeg o fis Mai - the eleventh of May
- yr ail ar hugain o fis Mai - the twenty-second of Mai
- yr unfed llyfr ar ddeg - the eleventh book
- yr ail lyfr ar hugain - the twenty-second book
So the initial part of the ordinal is still coming before the noun.