Problem with Kindle app dictionary

You have to install the dictionary. tap a word and if you haven't already, you should get a message that says... "Download Dictionary. To display definitions, download the free dictionary.

If you don't then maybe try deleting and reinstalling the Kindle app. You will need to download your books again, but that's a small price to get it working if you need it.

Beyond that, I think you would probably be better off asking in the Kindle iOS app support forum.

I had the same problem bud I found out how to solve it. Go to your Kindle account online and there you will see a list of your books as well as some other items - FREE DICTIONARIES! Click on the "Actions..." button on the right, select "Deliver to my..." and choose where you want to be able to use the dictionary. After that, the downloaded dictionary should remain in yout device.

He is talking about the built-in contextual dictionary used within Kindle books.