"Sororal"?

       Discussing twins, Connie asked whether two twins we knew were identical or fraternal.  Since both were female, I said (because they weren't identical), wouldn't it be "sororal," or is that even a word?  The Latin sources for the two words respectively are "brother" for "fraternal" and would be "sister" if "sororal" is a word.

       Well, yes exactly, "sororal" is a word and does apply to two female twins who are not identical; they are "sororal twins."