In the American English language edition the default Kindle dictionary is the New Oxford American dictionary. On other English language editions the Oxford Dictionary of English is available.
If you change the language of your Kindle it automatically provides a standard dictionary in the language chosen, depending on the region in the world where you bought your device, different language dictionaries are available. If you want to find out which ones are available to you, you can see the dictionaries in the cloud view of the Paperwhite.
It is a bit hidden, but I will show you how to find it: Turn on the view “Library” and choose “All”.
Here you navigate to the last page of your item list and you will see the folder “Dictionaries”. Open it and find all dictionaries that are available. Pick those you like and download them to your device.
Change the default language of your Kindle dictionary settings
Then you can change the default dictionary as follows: Tap the menu “Settings”/ “Language and Dictionaries” and then “Dictionaries”. Pick the language you want to edit. In our case it is “English” and the list of available dictionaries will appear. Change the default dictionary by tapping the radio button on the right. With “OK” you confirm the change of the default dictionary and can now use it.
More details on the use of dictionaries will be explained in the chapter “Learn a Language”.