What has Disney Copyrighted?

I have been inspired by the disney princesses to create a line of jewellery, but I want to use their names for the names of the pieces i made to represent them. I know that Disney can not copyright the names of the Princesses like Snow White and Cinderella as Disney did not create the names, but as to Tiana in the Princess and the frog, has Disney copyrighted that name? or is it possible to use it?