I can look up the definition of any word that I can select in iOS. However, once the dictionary is open, I can't figure out how to further look up the definition of a word that appears in the dictionary definition. This seems like basic dictionary software functionality. Is there a way to do it?
Nope, there is no way to do it. I think that’s really stupid. Though I remember being able to do that in iBooks when it was first released, before iOS had a built in dictionary.