"The Last Jedi" is wide open for interpretation.
1) As "Jedi" is also the plural form of the word, it could mean the last group indoctrinated into the fold.
2) It could be a reference to an off-shoot group of Jedi.
3) It could be a reference to the last group of Jedi trained by the original masters.
4) It could be a reference to only one person left in the universe with the ability to be a Jedi.
5) It could reference no more Jedi are needed as balance has been achieved, in the universe.
What is your take on it?