Our product has in the recent years grown and I think that to a new user, a different taxonomy would make more sense. The good thing is that we don't quite have too many existing users yet so I think this would be the best moment to do it. However, for the existing users, I'm not sure what's the best way to inform them that only a few names have changed inside the product, while everything else is still the same?
If the structure and functionality remains the same and the words are synonyms and they are not likely to be confused with other section or element of the page, I don't see a real problem.
Otherwise you could show a small notice or layover clarifying those changes the first time the enter the app after you applied the changes, to let them know that everything is the same as before, to prevent any confusion.
The updated taxonomy would explain the features better removing any ambiguity as much as possible. If this was achieved, there should not be a reason to explain to the users what the features do irrespective of what it did in the previous version. However, it will be wise to run the users through some general scenarios with tutorials – video or blog post. This will benefit both new and returning users. Using any available channel, pass the link to those tutorials along with the product update launch.