Exam technology

Hello,

We are reviewing the use of iPad dictionaries during exams.
We were using 3 different apps : 1 for English, 1 for French, 1 for bilingual FR-EN.

Our restrictions are as follows :

• No ads (paid version is fine if needed)
• Offline version

The apps we were using are in the most expensive end of the spectrum, and aren't reliable (frequent crash with 1 in particular).

Does anyone have good suggestions that they are using?

Thanks,