As with any serious study—and what could be more serious than this—involves a certain amount of new vocabulary. The Pali Canon, even though translated, is no exception: there are a lot of terms that many authors want you to understand in Pali, since there really is no good, or sufficient embracive English word to take there place.
This is the best dictionary I have found, but it is unfortunately out of print and can only be purchased used. I’ve provided the Amazon link for those if you click the image.
There is, however, also a pdf version of this, which you can find here.
Ulf Wolf