Medical dictionary for pages
Hi I'm using pages at university and I have to use a lot of technical words, but pages underline them even if they are right. I have a macbook pro so if I press my trackpad the macbook show me the dictionary with definitions of the word that I chose, if I search a technical word the dictionary finds it and it tells to me the right definition, so I can't understand why pages underline it even if it is in the dictionary and it already exists! I don't know how to choose italian oxford dictionary for pages instead of Apple dictionary.
Sorry for my terrible english I hope you understand my problem 😉.
Thanks in advice
MacBook Pro with Retina display, Mac OS X (10.0.x)