This offline bilingual dictionary contains tens of thousands of entries and allows you to search for translations of both English and French words. It also contains a phrasebook and verb conjugation resource. It is extremely useful in times when you don't have signal or do not want to pay extortionate roaming charges on holiday.
Please note - as this is a free version of the app it contains ads. Remember to turn off data on your phone to ensure ads are not downloaded when abroad.