Warning - This Post Contains SPOILERS
Lucasfilm knew exactly what it was doing when it titled the Star Wars: The Force Awakens sequel Star Wars: The Last Jedi. Ever since hearing that title for the first time, fans have been trying to speculate how it would factor into the movie's storyline.
With The Last Jedi officially opening in theaters, we now know exactly what the title means to both Episode VIII and the future of the Star Wars franchise. So, who is the titular "Last Jedi?" Well, there's actually a two-part answer:
The Old Master
In the first two acts of the movie, "The Last Jedi" refers to Luke Skywalker, who is the final vestige of The Jedi Order.
For Rey, Luke is "The Last Jedi" in the sense that he's the only one left in the entire galaxy who can teach her to harness the power of The Force that has been awakened inside her. For Kylo Ren and Snoke, Luke is simply the last Jedi they need to kill, in order to topple the balance of the Force over to the dark side, once and for all.
For Luke himself, the matter is more complicated. Luke is indeed the last Jedi Master in the galaxy when The Last Jedi takes place, but this is not a bad thing in Master Skywalker's eyes. Luke wants to be the Last Jedi, believing The Jedi Order to have been flawed and misguided to the point of hubris. In juicy reversal from Empire Strikes Back, Luke spends most of the film trying to teach Rey why not to become a Jedi - going so far as to burn the original texts (with help from Master Yoda's Force ghost).
The New Last Hope
By the time Star Wars: The Last Jedi reaches its climax, the entire concept of what "The Last Jedi" means gets flipped around to a new meaning. Luke being "The Last Jedi," was a title that carried a done of darkness and desperation; after Luke finds new faith in Rey, and passes on his teachings to her, it creates a far more hopeful tone for the term.
Luke can move on knowing that Rey will not in fact be "The Last Jedi" for long - though first she will need to either defeat or convert Ben Solo/Kylo Ren, who is hell-bent on erasing all traces of the past, and building his own future.
Will Rey still be The Last Jedi when Star Wars: Episode IX arrives? Or will we see a time jump like the one between Episode V and VI, in which we saw Luke go from fledgling student to full-on Jedi master? It's an important question, as it could be the difference between Rey being a struggling 'Last Jedi' in that film, or becoming a master and potential teacher, who has since recruited other Force users into the battle against Kylo Ren and The First Order.
Star Wars: The Lat Jedi will be in theaters on December 15th.